{"id":2692,"date":"2021-04-01T14:30:22","date_gmt":"2021-04-01T09:00:22","guid":{"rendered":"https:\/\/wordpress-505192-1602719.cloudwaysapps.com\/?p=2692"},"modified":"2021-04-01T16:40:29","modified_gmt":"2021-04-01T11:10:29","slug":"samacheer-kalvi-10th-science-solutions-chapter-8","status":"publish","type":"post","link":"https:\/\/samacheerkalviguru.com\/samacheer-kalvi-10th-science-solutions-chapter-8\/","title":{"rendered":"Samacheer Kalvi 10th Science Solutions Chapter 8 Periodic Classification of Elements"},"content":{"rendered":"

Students who are preparing for the Science exam can download this Tamilnadu State Board Solutions for Class 10th Science Chapter 8 from here for free of cost. These Tamilnadu State Board Textbook Solutions PDF cover all 10th Science Nuclear Physics Book Back Questions and Answers.<\/p>\n

All these concepts of Chapter 8 Periodic Classification of Elements are explained very conceptually by the subject teachers in Tamilnadu State Board Solutions PDF as per the prescribed Syllabus & guidelines. You can download Samacheer Kalvi 10th Science Book Solutions<\/a> Chapter 8 Periodic Classification of Elements State Board Pdf for free from the available links. Go ahead and get Tamilnadu State Board Class 10th Science Solutions of Chapter 8 Periodic Classification of Elements.<\/p>\n

Tamilnadu Samacheer Kalvi 10th Science Solutions Chapter 8 Periodic Classification of Elements<\/h2>\n

Kickstart your preparation by using this Tamilnadu State Board Solutions for Class 10th Science Chapter 8 Periodic Classification of Elements Questions and Answers and get the max score in the exams. You can cover all the topics of Chapter 8 easily after studying the Tamilnadu State Board Class 10th Science Textbook solutions pdf. Download the Tamilnadu State Board Science Chapter 8 Periodic Classification of Elements solutions of Class 10th by accessing the links provided here and ace up your preparation.<\/p>\n

Samacheer Kalvi 10th Science Periodic Classification of Elements Textual Evaluation Solved<\/h3>\n

I. Choose the best answer.<\/p>\n

Ex 3.14 Class 10 Samacheer Question 1.<\/strong>
\nThe number of periods and groups in the periodic table are ____.
\n(a) 6, 16
\n(b) 7, 17
\n(c) 8, 18
\n(d) 7, 18.
\nAnswer:
\n(d) 7, 48.<\/p>\n

10th Maths Exercise 3.14 Samacheer Kalvi Question 2.<\/strong>
\nThe basis of modern periodic law is:
\n(a) atomic number
\n(b) atomic mass
\n(c) isotopic mass
\n(d) number of neutrons
\nAnswer:
\n(a) atomic number<\/p>\n

Exercise 3.14 Class 10 Samacheer Question 3.<\/strong>
\n_____ group contains the member of the halogen family.
\n(a) 17th
\n(b) 15th
\n(c) 18th
\n(d) 16th.
\nAnswer:
\n(a) 17th<\/p>\n

10th Maths Exercise 3.14 Question 4.<\/strong>
\n……….is a relative periodic property.
\n(a) atomic radii
\n(b) ionic radii
\n(c) electron affinity
\n(d) electronegativity
\nAnswer:
\n(d) electronegativity<\/p>\n

10th Maths Exercise 3.14 Solutions Question 5.<\/strong>
\nChemical formula of rust is ____.
\n(a) FeO.xH2<\/sub>O
\n(b) FeO4<\/sub>.xH2<\/sub>O
\n(c) Fe2<\/sub>O3<\/sub>.xH2<\/sub>O
\n(d) FeO.
\nAnswer:
\n(c) Fe2<\/sub>O3<\/sub>.xH2<\/sub>O<\/p>\n

10th Maths Exercise 3.14 Solution Question 6.<\/strong>
\nIn the aluminothermic process the role of Al is ____.
\n(a) oxidizing agent
\n(b) reducing agent
\n(c) hydrogenating agent
\n(d) sulphurising agent.
\nAnswer:
\n(b) reducing agent<\/p>\n

Maths Book For Class 10 Samacheer Kalvi Question 7.<\/strong>
\nThe process of coating the surface of metal with a thin layer of zinc is called:
\n(a) painting
\n(b) thinning
\n(c) galvanization
\n(d) electroplating
\nAnswer:
\n(c) galvanization<\/p>\n

10th Samacheer Maths Question 8.<\/strong>
\nWhich of the following have inert gases 2 electrons in the outermost shell?
\n(a) He
\n(b) Ne
\n(c) Ar
\n(d) Kr.
\nAnswer:
\n(a) He<\/p>\n

Samacheer Kalvi 10th Guide Maths Question 9.<\/strong>
\nNeon shows zero electron affinity due to:
\n(a) stable arrangement of neutrons
\n(b) stable configuration of electrons
\n(c) reduced size
\n(d) increased density
\nAnswer:
\n(b) stable configuration of electrons<\/p>\n

10th Maths Solution Samacheer Kalvi Question 10.<\/strong>
\n____ is an important metal to form an amalgam.
\n(a) Ag
\n(b) Hg
\n(c) Mg
\n(d) Al.
\nAnswer:
\n(b) Hg<\/p>\n

II. Fill in the blanks.<\/p>\n

10th Standard Maths Algebra Question 1.<\/strong>
\nIf the electronegativity difference between two bonded atoms in a molecule is greater than 1.7, the nature of bonding is ____.
\nAnswer:
\nIonic bond.<\/p>\n

10th Maths Samacheer Question 2.<\/strong>
\n____ is the longest period in the periodical table.
\nAnswer:
\nSixth period.<\/p>\n

Maths Book Class 10 Samacheer Kalvi Question 3.<\/strong>
\n______ forms the basis of modem periodic table.
\nAnswer:
\nAtomic number.<\/p>\n

Question 4.
\nIf the distance between two Cl atoms in Cl2<\/sub> molecule is 1.98 \u00c5, then the radius of the Cl atom is ____.
\nAnswer:
\n0.99 \u00c5.<\/p>\n

Question 5.
\nAmong the given species A–<\/sup>, A+<\/sup>, and A, the smallest one in size is ______.
\nAnswer:
\nA+.<\/sup><\/p>\n

Question 6.
\nThe scientist who propounded the modem periodic law is ______.
\nAnswer:
\nHenry Moseley.<\/p>\n

Question 7.
\nAcross the period, ionic radii ______ (increases,decreases)
\nAnswer:
\nDecreases.<\/p>\n

Question 8.
\n_______ and ______ are called inner transition elements.
\nAnswer:
\nLanthanides and Actinides.<\/p>\n

Question 9.
\nThe chief ore of Aluminium is ______.
\nAnswer:
\nBauxite (Al2<\/sub>O3<\/sub>.2H2<\/sub>O).<\/p>\n

Question 10.
\nThe chemical name of rust is ______.
\nAnswer:
\nHydrated ferric oxide.<\/p>\n

III. Match the following.<\/p>\n

Question 1.<\/p>\n\n\n\n\n\n\n\n
1. Galvanisation<\/td>\n(a) Noble gas elements<\/td>\n<\/tr>\n
2. Calcination<\/td>\n(b) Coating with Zn<\/td>\n<\/tr>\n
3. Redox reaction<\/td>\n(c) Silver-tin amalgam<\/td>\n<\/tr>\n
4. Dental filling<\/td>\n(d) Alumino thermic process<\/td>\n<\/tr>\n
5. Group 18 elements<\/td>\n(e) Heating in the absence of air<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Answer:
\n1 – (b), 2 – (e), 3 – (d), 4 – (c), 5 – (a).<\/p>\n

IV. True or False: (If false give the correct statement)<\/p>\n

Question 1.
\nMoseley\u2019s periodic table is based on atomic mass.
\nAnswer:
\nFalse.
\nCorrect Statement: Moseley\u2019s periodic table is based on atomic number.<\/p>\n

Question 2.
\nIonic radius increases across the period from left to right.
\nAnswer:
\nFalse.
\nCorrect Statement: Ionic radius decreases across the period from left to right.
\nQuestion 3.
\nAll ores are minerals, but all minerals cannot be called as ores.
\nAnswer:
\nTrue.<\/p>\n

Question 4.
\nAl wires are used as electric cables due to their silvery – white colour.
\nAnswer:
\nFalse.
\nCorrect Statement: Al wires are used as electric cables due to their good conductor of electricity.<\/p>\n

Question 5.
\nAn alloy is a heterogeneous mixture of metals.
\nAnswer:
\nFalse.
\nCorrect Statement: An alloy is a homogenous mixture of metals.<\/p>\n

V. Assertion and Reason:<\/p>\n

Answer the following questions using the data given below.
\n(i) A and R are correct, R explains the A.
\n(ii) A is correct, R is wrong.
\n(iii) A is wrong, R is correct.
\n(iv) A and R are correct, R doesn\u2019t explain A.<\/p>\n

Question 1.
\nAssertion: The nature of bond in HF molecule is ionic
\nReason: The electronegativity difference between H and F is 1.9.
\nAnswer:
\n(i) A and R are correct, R explains the A.<\/p>\n

Question 2.
\nAssertion: Magnesium is used to protect steel from rusting.
\nReason: Magnesium is more reactive than iron.
\nAnswer:
\n(i) A and R are correct, R explains the A.<\/p>\n

Question 3.
\nAssertion: An uncleaned copper vessel is covered with a greenish layer.
\nReason: copper is not attacked by alkali
\nAnswer:
\n(iv) A and R are correct, R doesn\u2019t explain A.<\/p>\n

VI. Short Answer Questions.<\/p>\n

Question 1.
\nA is a reddish-brown metal, which combines with O2<\/sub> at < 1370 K gives B, a black coloured compound. At a temperature > 1370 K, A gives C which is red in colour. Find A, B and C with reaction.
\nAnswer:
\n(i) Reddish brown metal (A) is copper.<\/p>\n

(ii) (A) reacts with O2<\/sub> at bleow 1370 K gives Copper (II) oxide (B), which is black in colour.
\n2Cu + O2<\/sub> \\(\\xrightarrow [ 1370k ]{ below }\\) 2CuO (Copper (II) oxide) (B).<\/p>\n

(iii) (A) reacts with O2<\/sub> at above 1370 K gives Copper (I) oxide (C), which is red in colour.
\n\"Ex<\/p>\n

Question 2.
\nA is a silvery – white metal. A combines with O2<\/sub> to form B at 800\u00b0C, the alloy of A is used in making the aircraft. Find A and B.
\nAnswer:
\n(i) Silver – white metal (A) is Aluminium.<\/p>\n

(ii) (A) combines with O2<\/sub> to form aluminium oxide at 800\u00b0C.
\n\"10th<\/p>\n

(iii) Duralumin is the alloy of Al, which is used to make aircraft
\n\"Exercise<\/p>\n

Question 3.
\nWhat is rust? Give the equation for formation of rust.
\nAnswer:
\nRust is hydrated ferric oxide, Fe2<\/sub>O3<\/sub>.xH2<\/sub>O. It is formed when iron is exposed to moist air.
\n4 Fe + 3O2<\/sub> + xH2<\/sub>O > 2Fe2<\/sub>O3<\/sub>.xH2<\/sub>O<\/p>\n

Question 4.
\nState two conditions necessary for rusting of iron.
\nAnswer:
\nConditions for rusting of iron:<\/p>\n

    \n
  • The presence of water and oxygen is essential for the rusting of iron.<\/li>\n
  • Impurities in the iron, the presence of water vapour, acids, salts and carbon dioxide hasten to rust.<\/li>\n
  • Pure iron does not rust in dry and CO2<\/sub> free air. It also does not rust in pure water, free from dissolved salts.<\/li>\n<\/ul>\n

    VII. Long Answer Questions<\/p>\n

    Question 1.
    \n(a) State the reason for the addition of caustic alkali to bauxite ore during purification of bauxite.
    \n(b) Along with cryolite and alumina, another substance is added to the electrolyte mixture. Name the substance and give one reason for the addition.
    \nAnswer:
    \n(a) Naturally, Bauxite is not soluble in normal solvents. Therefore the addition of caustic alkali to bauxite plays an important role while extraction of aluminium. Caustic alkali dissolves bauxite forming soluble sodium meta aluminate while impurities remain insoluble and precipitate as red mud.
    \n\"10th<\/p>\n

    (b) Along with cryolite and alumina, another substance is added to the electrolyte mixture is Fluorspar. Adding of fluorspar lowers the fusion temperature of the electrolyte.<\/p>\n

    Question 2.
    \nThe electronic configuration of metal A is 2, 8, 18, 1. The metal A when exposed to air and moisture forms B a green layered compound. A with conc. H2<\/sub>SO4<\/sub> forms C and D along with water. D is a gaseous compound. Find A, B, C and D.
    \nAnswer:
    \n(i) The electronic configuration of metal (A) is 2, 8, 18, 1. A is copper (Z = 29)<\/p>\n

    (ii) (A) Copper exposed to air and moisture forms green layered compound (B) that is a copper carbonate.
    \n\"10th<\/p>\n

    (iii) Copper (A) reacts with conc.H2<\/sub>SO4<\/sub> to give copper sulphate (C) and Sulphur dioxide (D).
    \n\"10th<\/p>\n

    Question 3.
    \nExplain the smelting process.
    \nAnswer:
    \nSmelting (in a Blast Furnace): The charge consisting of roasted ore, coke and limestone in the ratio 8 : 4 : 1 is smelted in a blast furnace by introducing it through the cup and cone arrangement at the top. There are three important regions in the furnace.
    \n\"Maths
    \n(a) The Lower Region (Combustion Zone): The temperature is at 1500\u00b0C. In this region, coke bums with oxygen to form CO2<\/sub> when the charge comes in contact with a hot blast of air.
    \n\"10th
    \nIt is an exothermic reaction since heat is liberated.<\/p>\n

    (b) The Middle Region (Fusion Zone): The temperature prevails at 1000\u00b0C. In this region, CO2<\/sub> is reduced to CO.
    \n\"Samacheer
    \nLimestone decomposes to calcium oxide and CO2<\/sub>
    \n\"10th
    \nThese two reactions are endothermic due to absorption of heat. Calcium oxide combines with silica to form calcium silicate slag.
    \nCaO + SiO2<\/sub> \u2192 CaSiO3<\/sub><\/p>\n

    (c) The Upper Region (Reduction Zone): The temperature prevails at 400\u00b0C . In this region carbon monoxide reduces ferric oxide to form a fairly pure spongy iron.
    \n\\(\\mathrm{Fe}_{2} \\mathrm{O}_{3}+3 \\mathrm{CO} \\stackrel{400^{\\circ} \\mathrm{C}}{\\longrightarrow} 2 \\mathrm{Fe}+3 \\mathrm{CO}_{2}\\)
    \nThe molten iron is collected at the bottom of the furnace after removing the slag.
    \nThe iron thus formed is called pig iron. It is remelted and cast into different moulds. This iron is called cast iron.<\/p>\n

    VIII. HOT Questions.<\/p>\n

    Question 1.
    \nMetal A belongs to period 3 and group 13. A in red hot condition reacts with steam to form B. A with strong alkali forms C. Find A, B and C with reactions.
    \nAnswer:
    \n(i) Metal (A) belongs to period 3 and group 13, is Aluminium (Al).<\/p>\n

    (ii) (A) Al in red hot condition reacts with steam to form Aluminium oxide (B).
    \n\"10th<\/p>\n

    (iii) Aluminium (A) reacts with strong alkali forms of sodium meta aluminate (C).
    \n\"Maths<\/p>\n

    Question 2.
    \nName the acid that renders aluminium passive. Why?
    \nAnswer:
    \nDil. or cone. HNO3<\/sub> does not attack aluminium, but renders Al passive due to the formation of oxide film on its surface.<\/p>\n

    Question 3.
    \n(a) Identify the bond between H and F in the HF molecule.
    \n(b) What property forms the basis of identification?
    \n(c) How does the property7 vary in periods and in groups?
    \nAnswer:
    \n(a) The nature of the bond in the HF molecule is ionic.
    \n(b) Electronegativity.
    \n(c) Along the period, from left to right in the periodic table the electronegativity increases because of the increase in the nuclear charge which in turn attracts the electrons more strongly. On moving down a group, the electronegativity of the elements decreases because of the increased number of energy levels.<\/p>\n

    Samacheer Kalvi 10th Science Periodic Classification of Elements Additional Questions Solved<\/h3>\n

    I. Choose the best answer.<\/p>\n

    Question 1.
    \nWhich period contains only two elements?
    \n(a) Second
    \n(b) First
    \n(c) Third
    \n(d) Fifth.
    \nAnswer:
    \n(b) First<\/p>\n

    Question 2.
    \nThe sixth period contains inner transition elements.
    \n(a) 18
    \n(b) 14
    \n(c) 10
    \n(d) 8
    \nAnswer:
    \n(b) 14<\/p>\n

    Question 3.
    \nLanthanides and Actinides are called as _____.
    \n(a) Alkali metals
    \n(b) Inner transition elements
    \n(c) Transition elements
    \n(d) Representative elements.
    \nAnswer:
    \n(b) Inner transition elements<\/p>\n

    Question 4.
    \nThe number of valence electrons present in Halogens is:
    \n(a) One
    \n(b) Seven
    \n(c) Zero
    \n(d) Two
    \nAnswer:
    \n(b) Seven<\/p>\n

    Question 5.
    \nThe distance between the two hydrogen nuclei of the molecule is 0.74 \u00c5. So its covalent radius is _____.
    \n(a) 0.74 \u00c5
    \n(b) 0.99 \u00c5
    \n(c) 0.37 \u00c5
    \n(d) 7.4 \u00c5.
    \nAnswer:
    \n(c) 0.37 \u00c5<\/p>\n

    Question 6.
    \nAlong the groups, atomic radius _____.
    \n(a) decreases
    \n(b) increases
    \n(c) decreases then increase
    \n(d) no change.
    \nAnswer:
    \n(b) increases.<\/p>\n

    Question 7.
    \nWhich one of the following elements will have the highest electronegativity?
    \n(a) chlorine
    \n(b) nitrogen
    \n(c) caesium
    \n(d) fluorine
    \nAnswer:
    \n(d) fluorine<\/p>\n

    Question 8.
    \nElectron affinity is measured in _____.
    \n(a) kJ-1<\/sup>
    \n(b) mol-1<\/sup>
    \n(c) kJ\/mol
    \n(d) kJ\/mol2<\/sup>.<\/span>
    \nAnswer:
    \n(c) kJ\/mol<\/p>\n

    Question 9.
    \nNoble gases have ______ electron affinity.
    \n(a) positive
    \n(b) negative
    \n(c) zero
    \n(d) high.
    \nAnswer:
    \n(c) zero<\/p>\n

    Question 10.
    \nThe element with positive electron gain enthalpy is:
    \n(a) Hydrogen
    \n(b) Sodium
    \n(c) Argon
    \n(d) Fluorine
    \nAnswer:
    \n(b) Sodium<\/p>\n

    Question 11.
    \nThe mineral from which a metal can be readily and economically extracted on a large scale is said to be a \/ an _____.
    \n(a) Ore
    \n(b) Flux
    \n(c) Slag
    \n(d) Gangue.
    \nAnswer:
    \n(a) Ore<\/p>\n

    Question 12.
    \nFlux + Gangue \u2192 _____?
    \n(a) Mineral
    \n(b) Matrix
    \n(c) Slag
    \n(d) Smog.
    \nAnswer:
    \n(c) Slag<\/p>\n

    Question 13.
    \n………… is used for anodizing process.
    \n(a) Zinc
    \n(b) iron
    \n(c) Aluminium
    \n(d) Tin
    \nAnswer:
    \n(c) Aluminium<\/p>\n

    Question 14.
    \nThe ore which can be purified by gravity separation method is _____.
    \n(a) Haematite
    \n(b) oxide ores
    \n(c) sulphide ores
    \n(d) both (a) and (b).
    \nAnswer:
    \n(d) both (a) and (b).<\/p>\n

    Question 15.
    \nThe calcium silicate slag is formed in ………. zone.
    \n(a) combustion zone
    \n(b) fusion zone
    \n(c) reduction
    \n(d) molten
    \nAnswer:
    \n(b) fusion zone<\/p>\n

    Question 16.
    \nZinc blende is purified by _____.
    \n(a) Hydraulic method
    \n(b) Magnetic separation method
    \n(c) Froth floatation method
    \n(d) Chemical method.
    \nAnswer:
    \n(c) Froth floatation method<\/p>\n

    Question 17.
    \nBauxite ore is purified by _____.
    \n(a) Leaching process
    \n(b) Hydraulic method
    \n(c) Froth floatation method
    \n(d) Magnetic separation method.
    \nAnswer:
    \n(a) Leaching process<\/p>\n

    Question 18.
    \nWhen copper reacts with dil.HNO3<\/sub> it liberates …………. gas.
    \n(a) SO2<\/sub>
    \n(b) NO2<\/sub>
    \n(C) CO2<\/sub>
    \n(d) NO
    \nAnswer:
    \n(d) NO<\/p>\n

    Question 19.
    \nWhich metal process low melting point?
    \n(a) Gallium
    \n(b) Caesium
    \n(c) Aluminium
    \n(d) Copper.
    \nAnswer:
    \n(a) Gallium<\/p>\n

    Question 20.
    \nWhich one of the following is not an ore of aluminium?
    \n(a) Bauxite
    \n(b) Haematite
    \n(c) Cryolite
    \n(d) Corundum.
    \nAnswer:
    \n(b) Haematite<\/p>\n

    Question 21.
    \n……….. is stored in Kerosene.
    \n(a) Iron
    \n(b) Silver
    \n(c) Sodium
    \n(d) Aluminium
    \nAnswer:
    \n(c) Sodium<\/p>\n

    Question 22.
    \nElectrolytic reduction of alumina into aluminium is ______.
    \n(a) Hall’s process
    \n(b) Alumino thermic process
    \n(c) Baeyer’s process
    \n(d) Bessemerisation process.
    \nAnswer:
    \n(a) Hall’s process<\/p>\n

    Question 23.
    \nIn Hall’s process, cathode used is ______.
    \n(a) Iron tank
    \n(b) Graphite
    \n(c) Pure alumina
    \n(d) Iron tank linked with graphite.
    \nAnswer:
    \n(d) Iron tank linked with graphite.<\/p>\n

    Question 24.
    \nThe metal oxides are usually……….. in nature.
    \n(a) basic
    \n(b) acidic
    \n(c) amphoteric
    \n(d) neither acidic nor basic
    \nAnswer:
    \n(a) basic<\/p>\n

    Question 25.
    \nA silvery-white metal is ______.
    \n(a) Aluminium
    \n(b) Copper
    \n(c) Iron
    \n(d) Zinc.
    \nAnswer:
    \n(a) Aluminium<\/p>\n

    Question 26.
    \nAluminium reacts with NaOH to give ______.
    \n(a) Al2<\/sub>O3<\/sub>
    \n(b) AlCl3<\/sub>
    \n(c) NaAlO2<\/sub>
    \n(d) Al(OH)3<\/sub>
    \nAnswer:
    \n(c) NaAlO2<\/sub><\/p>\n

    Question 27.
    \nAtoms of the elements belonging to the same group of periodic table will have:
    \n(a) same number of protons
    \n(b) same number of electrons in the valence shell
    \n(c) same number of neutrons
    \n(d) same number of electrons
    \nAnswer:
    \n(b) same number of electrons in the valence shell<\/p>\n

    Question 28.
    \nChief ore of copper is ______.
    \n(a) CuFeS2<\/sub>
    \n(b) Cu2<\/sub>O
    \n(c) Cu2<\/sub>S
    \n(d) CuSO4<\/sub>
    \nAnswer:
    \n(a) CuFeS2<\/sub><\/p>\n

    Question 29.
    \nMolecular formula for copper pyrites ______.
    \n(a) Cu2<\/sub>O
    \n(b) Cu2<\/sub>S
    \n(c) CuCO3<\/sub>
    \n(d) CuFeS2<\/sub>
    \nAnswer:
    \n(d) CuFeS2<\/sub><\/p>\n

    Question 30.
    \nThe electronegativity of fluorine is:
    \n(a) 4.0
    \n(b) 3
    \n(c) 2.8
    \n(d) 2.1
    \nAnswer:
    \n(a) 4.0<\/p>\n

    Question 31.
    \nThe second most abundant metal available next to aluminium is ______.
    \n(a) Cu
    \n(b) Ag
    \n(c) Au
    \n(d) Fe.
    \nAnswer:
    \n(d) Fe.<\/p>\n

    Question 32.
    \nMost important ore of iron is ______.
    \n(a) Haematite
    \n(b) Magnetite
    \n(c) Iron pyrite
    \n(d) Cryolite.
    \nAnswer:
    \n(a) Haematite<\/p>\n

    Question 33.
    \nThe volatile impurities present in haematite are:
    \n(a) Carbon and Nitrogen
    \n(b) Oxygen and Nitrogen
    \n(c) Helium and Oxygen
    \n(d) Sulphur and Phosphorus
    \nAnswer:
    \n(d) Sulphur and Phosphorus<\/p>\n

    Question 34.
    \nThe solute present in brass is:
    \n(a) copper
    \n(b) zinc
    \n(c) tin
    \n(d) magnesium
    \nAnswer:
    \n(b) zinc<\/p>\n

    Question 35.
    \nWhich one of the following is used for making pressure cookers?
    \n(a) Brass
    \n(b) Magnalium
    \n(c) Duralumin
    \n(d) Nickel steel
    \nAnswer:
    \n(c) Duralumin<\/p>\n

    Question 36.
    \nWhich is used as propeller?
    \n(a) Stainless steel
    \n(b) Nickel steel
    \n(c) Brass
    \n(d) Magnalium.
    \nAnswer:
    \n(b) Nickel steel<\/p>\n

    Question 37.
    \nGold does not occur in the combined form. It does not react with air or water. It is in the ______ state.
    \n(a) native
    \n(b) combined
    \n(c) complex
    \n(d) molten.
    \nAnswer:
    \n(a) native<\/p>\n

    Question 38.
    \nWhich of the following metal is not found in a free state?
    \n(a) Ag
    \n(b) Au
    \n(c) Pt
    \n(d) Al.
    \nAnswer:
    \n(d) Al.<\/p>\n

    Question 39.
    \nWhich one of the following does not react with copper?
    \n(a) Oxygen
    \n(b) Conc.H2<\/sub>SO4<\/sub>
    \n(c) NaOH
    \n(d) Conc.HNO3<\/sub>
    \nAnswer:
    \n(c) NaOH<\/p>\n

    Question 40.
    \nAn element which is an essential constituent of all organic compounds belongs to ______ group.
    \n(a) 14th
    \n(b) 15th
    \n(c) 16th
    \n(d) 17th.
    \nAnswer:
    \n(a) 14th<\/p>\n

    Question 41.
    \nThe highest ionization energy is exhibited by ______.
    \n(a) Halogens
    \n(b) Alkaline earth metals
    \n(c) Transition metals
    \n(d) Nobel gases.
    \nAnswer:
    \n(d) Nobel gases.<\/p>\n

    Question 42.
    \nWhich two elements of the following belongs to the same period? (Al, Si, Ba, O).
    \n(a) Si, Ba
    \n(b) Al, Ba
    \n(c) Al, Si
    \n(d) Al, O.
    \nAnswer:
    \n(c) Al, Si<\/p>\n

    Question 43.
    \n98% pure copper and 2% impurities is called ______.
    \n(a) Matte
    \n(b) Copper pyrites
    \n(c) blister copper
    \n(d) cuprite.
    \nAnswer:
    \n(c) blister copper<\/p>\n

    Question 44.
    \n_____ is used in making anchors and electromagnets.
    \n(a) Steel
    \n(b) Pig iron
    \n(c) Cast iron
    \n(d) Wrought iron.
    \nAnswer:
    \n(d) Wrought iron.<\/p>\n

    Question 45.
    \nWhich reagent does not react with iron?
    \n(a) Conc. HNO3<\/sub>
    \n(b) Conc.H2<\/sub>SO4<\/sub>
    \n(c) Steam
    \n(d) Dil. HNO3<\/sub>
    \nAnswer:
    \n(a) Conc. HNO3<\/sub><\/p>\n

    II. Fill in the blanks.<\/p>\n

    Question 1.
    \nMatte is a mixture of ______.
    \nAnswer:
    \nCu2<\/sub>S + FeS.<\/p>\n

    Question 2.
    \nSecond group elements are called ______.
    \nAnswer:
    \nAlkaline earth metals.<\/p>\n

    Question 3.
    \nIonisation energy is measured in _____ unit.
    \nAnswer:
    \nkJ\/mol<\/p>\n

    Question 4.
    \nThe ionisation energy ______ along the period.
    \nAnswer:
    \nIncreases.<\/p>\n

    Question 5.
    \n______ property, which predicts the nature of bonding between the atoms in a molecule.
    \nAnswer:
    \nElectronegativity.<\/p>\n

    Question 6.
    \nIf the difference in electronegativity between two elements is 1.7, the bond has ____ and _____.
    \nAnswer:
    \n50% ionic character, 50% covalent character.<\/p>\n

    Question 7.
    \nIf the difference in electronegativity between two elements is less than 1.7, the bond is considered to be ______.
    \nAnswer:
    \nCovalent.<\/p>\n

    Question 8.
    \nIf the difference in electronegativity between two elements is greater than 1.7, the bond is considered to be ______.
    \nAnswer:
    \nIonic.<\/p>\n

    Question 9.
    \nThe process of extracting the ores from the earth’s crust is called ______.
    \nAnswer:
    \nMining.<\/p>\n

    Question 10.
    \n______ is the main principle behind in Hydraulic method.
    \nAnswer:
    \nSpecific gravity.<\/p>\n

    Question 11.
    \nFroth floatation process is preferable for ______ ores.
    \nAnswer:
    \nLighter
    \n(or)
    \nSulphide.<\/p>\n

    Question 12.
    \nOn heating in air, iron forms ______.
    \nAnswer:
    \nFe3<\/sub>O4<\/sub><\/p>\n

    Question 13.
    \nIron reacts with Chlorine to form _____ compound.
    \nAnswer:
    \nFerric chloride.<\/p>\n

    Question 14.
    \nThe corrosive action in the absence of moisture is called ______.
    \nAnswer:
    \nDry corrosion.<\/p>\n

    Question 15.
    \n______ technique used to renovate the Pamban bridge.
    \nAnswer:
    \nProtective coating.<\/p>\n

    Question 16.
    \nThe atomic number is the number of ____ in the nucleus or number of ______ revolving around the nucleus in an atom.
    \nAnswer:
    \nProtons, electrons.<\/p>\n

    Question 17.
    \nThe long form of periodic table is based upon the _____ of elements.
    \nAnswer:
    \nElectronic configuration.<\/p>\n

    Question 18.
    \nIn the periodic table, the horizontal rows are called _____ and vertical columns are called ______.
    \nAnswer:
    \nPeriods, groups.<\/p>\n

    Question 19.
    \nThe modem periodic table has been divided into ______ blocks known as _______ blocks.
    \nAnswer:
    \nFour, s, p, d, f<\/p>\n

    Question 20.
    \nThe ______ of the elements in a period decreases from left to right and the atomic radii of the elements present in a group downwards.
    \nAnswer:
    \nAtomic size, increases.<\/p>\n

    Question 21.
    \n_______ period is the longest period and it contains ______ elements.
    \nAnswer:
    \nSeventh, 32.<\/p>\n

    Question 22.
    \nIn the periodic table, there are ______ groups and _____ periods.
    \nAnswer:
    \n18, 7.<\/p>\n

    Question 23.
    \nMetals like Ti, Cr, Mn, Zr find their application in the manufacturing of defence equipment called ______.
    \nAnswer:
    \nStrategic metals.<\/p>\n

    Question 24.
    \nThe metal ______ plays a vital role in nuclear reactions releasing nuclear energy and used in nuclear weapons.
    \nAnswer:
    \nUranium.<\/p>\n

    Question 25.
    \nCopper, silver and gold are called _______ as they are used in making ____ and ______.
    \nAnswer:
    \nCoinage metals, coins and jewellery.<\/p>\n

    Question 26.
    \nPurity of gold is expressed in ______ and ______ is pure gold.
    \nAnswer:
    \nCarats, 24 – carat gold.<\/p>\n

    Question 27.
    \n_______ is an ore of aluminium and _____ is its mineral.
    \nAnswer:
    \nBauxite, clay.<\/p>\n

    Question 28.
    \nAll ______ cannot be called as ores but all ______ are minerals.
    \nAnswer:
    \nMinerals, ores.<\/p>\n

    Question 29.
    \nThe process of extracting the ores from the earth\u2019s crust is called ______.
    \nAnswer:
    \nMining.<\/p>\n

    Question 30.
    \nThe rocky impurity associated with the ore is called ____ or ______.
    \nAnswer:
    \nGangue, matrix.<\/p>\n

    Question 31.
    \n_____ is a substance added to the ore to reduce the fusion temperature and to remove impurities.
    \nAnswer:
    \nFlux.<\/p>\n

    Question 32.
    \n____ is the process of reducing the roasted metallic oxide to metal.
    \nAnswer:
    \nSmelting.<\/p>\n

    Question 33.
    \nSlag is the fusible product formed when ____ reacts with ____ during the extraction of metals.
    \nAnswer:
    \nFlux, gangue<\/p>\n

    Question 34.
    \nThe temperature applied in Hall\u2019s process is _____ and the voltage used in ______.
    \nAnswer:
    \n900 – 950\u00b0C, 5 – 6V<\/p>\n

    Question 35.
    \n_____ is used in making manhole covers and drain pipes and _______ is used in making transmission cables and T.V. towers.
    \nAnswer:
    \nPig iron, steel.<\/p>\n

    Question 36.
    \n______ is defined as the slow and steady destruction of a metal by the environment.
    \nAnswer:
    \nCorrosion.<\/p>\n

    Question 37.
    \n_______ is a process of coating zinc on iron sheets by using electric current.
    \nAnswer:
    \nGalvanization.<\/p>\n

    III. Match the following.<\/p>\n

    Question 1.<\/p>\n\n\n\n\n\n\n\n
    i. Boron family<\/td>\n(a) Group 17<\/td>\n<\/tr>\n
    ii. Carbon family<\/td>\n(b) Group 16<\/td>\n<\/tr>\n
    iii. Nitrogen family<\/td>\n(c) Group 13<\/td>\n<\/tr>\n
    iv. Chalcogen family<\/td>\n(d) Group 15<\/td>\n<\/tr>\n
    v. Halogen family<\/td>\n(e) Group 14<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    Answer:
    \ni – c, ii – e, iii – d, iv – b , v – a.<\/p>\n

    Question 2.<\/p>\n\n\n\n\n\n\n
    i. Alkali metals<\/td>\n(a) Lanthanides & Actinides<\/td>\n<\/tr>\n
    ii. Alkaline earth metals<\/td>\n(b) Groups 3 \u2013 12<\/td>\n<\/tr>\n
    iii. Transition elements<\/td>\n(c) Group 2<\/td>\n<\/tr>\n
    iv. Inner transition elements<\/td>\n(d) Group 1<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    Answer:
    \ni – d, ii – c, iii – b, iv – a.<\/p>\n

    Question 3.<\/p>\n\n\n\n\n\n\n
    i. Group 18<\/td>\n(a) Main group elements<\/td>\n<\/tr>\n
    ii. Group 3 \u2013 12<\/td>\n(b) Noble gases<\/td>\n<\/tr>\n
    iii. Group 13 \u2013 18<\/td>\n(c) Halogens<\/td>\n<\/tr>\n
    iv. Group 17<\/td>\n(d) Transition elements<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    Answer:
    \ni – b, ii – d, iii – a, iv – c.<\/p>\n

    Question 4.<\/p>\n\n\n\n\n\n\n
    i. Copper<\/td>\n(a) Lustrous greyish white metal<\/td>\n<\/tr>\n
    ii. Iron<\/td>\n(b) Cn 112<\/td>\n<\/tr>\n
    iii. Aluminium<\/td>\n(c) Reddish-brown metal<\/td>\n<\/tr>\n
    iv. Copernicium<\/td>\n(d) Silvery white metal<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    Answer:
    \ni – c, ii – a, iii – d, iv – b.<\/p>\n

    Question 5.<\/p>\n\n\n\n\n\n\n\n
    Alloys<\/strong><\/td>\nComposition<\/strong><\/td>\n<\/tr>\n
    i. Brass<\/td>\n(a) Al, Mg, Mn, Cu<\/td>\n<\/tr>\n
    ii. Duralumin<\/td>\n(b) Cu, Zn<\/td>\n<\/tr>\n
    iii. Bronze<\/td>\n(c) Al, Mg<\/td>\n<\/tr>\n
    iv. Magnalium<\/td>\n(d) Cu, Sn<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    Answer:
    \ni – b, ii – a, iii – d, iv – c.<\/p>\n

    Question 6.<\/p>\n\n\n\n\n\n\n\n
    Elements<\/strong><\/td>\nElectronegative value<\/strong><\/td>\n<\/tr>\n
    i. F<\/td>\n(a) 2.5<\/td>\n<\/tr>\n
    ii. Cl<\/td>\n(b) 2.8<\/td>\n<\/tr>\n
    iii. Br<\/td>\n(c) 3.0<\/td>\n<\/tr>\n
    iv. I<\/td>\n(d) 4.0<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    Answer:
    \ni – d, ii – c, iii – b, iv – a.<\/p>\n

    Question 7.<\/p>\n\n\n\n\n\n\n\n
    Process<\/strong><\/td>\nOres<\/strong><\/td>\n<\/tr>\n
    i. Hydraulic process<\/td>\n(a) ZnS<\/td>\n<\/tr>\n
    ii. Magnetic separation<\/td>\n(b) Fe2<\/sub>O3<\/sub><\/td>\n<\/tr>\n
    iii. Froth floatation process<\/td>\n(c) SnO2<\/sub><\/td>\n<\/tr>\n
    iv. Leaching process<\/td>\n(d) Al2<\/sub>O3<\/sub>. 2H2<\/sub>O<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    Answer:
    \ni – b, ii – c, iii – a, iv – d.<\/p>\n

    Question 8.<\/p>\n\n\n\n\n\n\n
    i. Cuprite<\/td>\n(a) Halide ore<\/td>\n<\/tr>\n
    ii. Marble<\/td>\n(b) Oxide ore<\/td>\n<\/tr>\n
    iii. Fluorspar<\/td>\n(c) Sulphide ore<\/td>\n<\/tr>\n
    iv. Galena<\/td>\n(d) Carbonate ore<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    Answer:
    \ni – b, ii – d, iii – a, iv – c.<\/p>\n

    Question 9.<\/p>\n\n\n\n\n\n\n\n\n\n
    Alloy<\/strong><\/td>\nMetals present<\/strong><\/td>\nUses<\/strong><\/td>\n<\/tr>\n
    1. Brass<\/td>\nFe, C, Ni<\/td>\nStatues, Coins<\/td>\n<\/tr>\n
    2. Bronze<\/td>\nAl, Mg, Mn, Cu<\/td>\nAircraft, Pressure cookers<\/td>\n<\/tr>\n
    3. Duralumin<\/td>\nFe, C, Ni, Cr<\/td>\nCables, Propeller<\/td>\n<\/tr>\n
    4. Magnalium<\/td>\nCu, Sn<\/td>\nAutomobile parts, Utensils<\/td>\n<\/tr>\n
    5. Stainless steel<\/td>\nCu, Zn<\/td>\nScientific instruments, Air craft<\/td>\n<\/tr>\n
    6. Nickel steel<\/td>\nAl, Mg<\/td>\nMedals, decorative items<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    Answer:<\/p>\n\n\n\n\n\n\n\n\n\n
    Alloy<\/strong><\/td>\nMetals present<\/strong><\/td>\nUses<\/strong><\/td>\n<\/tr>\n
    1. Brass<\/td>\nCu, Zn<\/td>\nMedals, decorative items<\/td>\n<\/tr>\n
    2. Bronze<\/td>\nCu, Sn<\/td>\nStatues, Coins<\/td>\n<\/tr>\n
    3. Duralumin<\/td>\nAl, Mg, Mn, Cu<\/td>\nAircraft, Pressure cookers<\/td>\n<\/tr>\n
    4. Magnalium<\/td>\nAl, Mg<\/td>\nScientific instruments, Air craft<\/td>\n<\/tr>\n
    5. Stainless steel<\/td>\nFe, C, Ni, Cr<\/td>\nAutomobile parts, Utensils<\/td>\n<\/tr>\n
    6. Nickel steel<\/td>\nFe, C, Ni<\/td>\nCables, Propeller<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    Question 10.<\/p>\n\n\n\n\n\n\n\n
    Metal<\/strong><\/td>\nOre<\/strong><\/td>\nChemical formula<\/strong><\/td>\n<\/tr>\n
    1. Copper<\/td>\nBauxite<\/td>\nZnCO3<\/sub><\/td>\n<\/tr>\n
    2. Aluminium<\/td>\nHaematite<\/td>\nCuFeS2<\/sub><\/td>\n<\/tr>\n
    3. Iron<\/td>\nCopper pyrite<\/td>\nFe2<\/sub>O3<\/sub><\/td>\n<\/tr>\n
    4. Zinc<\/td>\nCalamine<\/td>\nAl2<\/sub>O3<\/sub>.2H2<\/sub>O<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    Answer:<\/p>\n\n\n\n\n\n\n\n
    Metal<\/strong><\/td>\nOre<\/strong><\/td>\nChemical formula<\/strong><\/td>\n<\/tr>\n
    1. Copper<\/td>\nCopper pyrite<\/td>\nCuFeS2<\/sub><\/td>\n<\/tr>\n
    2. Aluminium<\/td>\nBauxite<\/td>\nAl2<\/sub>O3<\/sub>.2H2<\/sub>O<\/td>\n<\/tr>\n
    3. Iron<\/td>\nHaematite<\/td>\nFe2<\/sub>O3<\/sub><\/td>\n<\/tr>\n
    4. Zinc<\/td>\nCalamine<\/td>\nZnCO3<\/sub><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    IV. State whether true or false. If false, give the correct statement.<\/p>\n

    Question 1.
    \nFirst period contains only one element.
    \nAnswer:
    \nFalse.
    \nCorrect Statement: First period contains two elements.(Hydrogen & Ftelium)<\/p>\n

    Question 2.
    \nThe valency of all alkali metals is one.
    \nAnswer:
    \nTrue.
    \nQuestion 3.
    \nNoble gases are more reactive.
    \nAnswer:
    \nFalse.
    \nCorrect Statement: Noble gases are less reactive.<\/p>\n

    Question 4.
    \nThe atomic radius decreases from Li to B?
    \nAnswer:
    \nTrue.<\/p>\n

    Question 5.
    \nAs the positive charge increases, the size of the cation also increases.
    \nAnswer:
    \nFalse.
    \nCorrect Statement: As the positive charge increases, the size of the cation also decreases.<\/p>\n

    Question 6.
    \nCopper pyrite ore is concentrated by gravity separation method.
    \nFalse
    \nCorrect Statement: Copper pyrite ore is concentrated by froth floatation process.<\/p>\n

    Question 7.
    \nAluminium alloyed with gold and silver for making coins and jewels.
    \nAnswer:
    \nFalse.
    \nCorrect Statement: Copper alloyed with gold and silver for making coins and jewels.<\/p>\n

    Question 8.
    \nThe corrosive action in the presence of moisture is called wet corrosion.
    \nAnswer:
    \nTrue<\/p>\n

    Question 9.
    \nThe physical and chemical properties of elements are the periodic function of their atomic numbers – modern periodic law.
    \nAnswer:
    \nTrue.<\/p>\n

    Question 10.
    \nThe long form of periodic table consists of horizontal rows called groups and vertical columns called periods.
    \nAnswer:
    \nFalse.
    \nCorrect statement: The long form of periodic table consists of horizontal rows called periods and vertical columns called groups.<\/p>\n

    Question 11.
    \nThe first period in the periodic table is the shortest period and contains 8 elements from Lithium to Neon.
    \nAnswer:
    \nFalse.
    \nCorrect statement: The first period in the periodic table is the shortest period and contains 2 elements Hydrogen and Helium.
    \n(OR)
    \nThe second period in the periodic table is the short period and contains 8 elements from Lithium to Neon.<\/p>\n

    Question 12.
    \nThe sixth period in the periodic table is the longest period and contains 32 elements.
    \nAnswer:
    \nTrue.<\/p>\n

    Question 13.
    \nGroup 1, 2 and 13 – 18 are called normal elements.
    \n(or)
    \nMain group elements.
    \n(or)
    \nRepresentative elements.
    \nAnswer:
    \nTrue.<\/p>\n

    Question 14.
    \nThe atomic size of the elements in a period increases from left to right.
    \nAnswer:
    \nFalse.
    \nCorrect statement: The atomic size of the elements in a period decreases from left to right.<\/p>\n

    Question 15.
    \nIn a period, the metallic character of the element increases while their non-metallic character decreases.
    \nAnswer:
    \nFalse.
    \nCorrect statement: In a period, the metallic character of the element decreases while their non-metallic character increases.<\/p>\n

    Question 16.
    \nThe last element authenticated by IUPAC is Cn 112 [Copemicium].
    \nAnswer:
    \nTrue.<\/p>\n

    Question 17.
    \nSilver was the first metal to be used in making utensils and weapons.
    \nAnswer:
    \nFalse.
    \nCorrect statement: Copper was the first metal to be used in making utensils and weapons.<\/p>\n

    Question 18.
    \nThe strategic metals such as copper, silver and gold are used in the manufacturing of defence equipment.
    \nAnswer:
    \nFalse.
    \nCorrect statement: The strategic metals such as titanium, chromium manganese, zirconium are used in the manufacturing of defence equipment.<\/p>\n

    Question 19.
    \nCopper, silver and gold are called coinage metals.
    \nAnswer:
    \nTrue.<\/p>\n

    Question 20.
    \nFor making ornaments, 24 – carat gold is used which is pure gold.
    \nAnswer:
    \nFalse.
    \nCorrect statement: For making ornaments, 22 – carat gold is used which contains 22 parts of gold by weight and 2 parts of copper by weight.<\/p>\n

    Question 21.
    \nThe mineral from which a metal can be readily and economically extracted on a large scale is said to be ore.
    \nAnswer:
    \nTrue.<\/p>\n

    Question 22.
    \nThe rocky impurity associated with the ore is called flux.
    \nAnswer:
    \nFalse.
    \nCorrect statement: The rocky impurity associated with the ore is called gangue or matrix.<\/p>\n

    Question 23.
    \nSlag is the fusible product formed when flux reacts with gangue during the extraction of metals.
    \nAnswer:
    \nTrue.<\/p>\n

    Question 24.
    \nMetals which have high chemical reactivity are found in a free state or in the native state.
    \nAnswer:
    \nFalse.
    \nCorrect statement: Metals which have low chemical reactivity are found in a free state or in the native state.<\/p>\n

    Question 25.
    \nAluminium is the metal found most abundantly in the earth\u2019s crust.
    \nAnswer:
    \nTrue<\/p>\n

    Question 26.
    \nAluminium is a reddish-brown metal and it is a bad conductor of heat and electricity.
    \nAnswer:
    \nFalse.
    \nCorrect statement: Aluminium is a silvery – white metal and it is a good conductor of heat and electricity.
    \nQuestion 27.
    \nAluminium reacts with strong caustic alkalis forming aluminates.
    \nAnswer:
    \nTrue<\/p>\n

    Question 28.
    \nConc. Nitric acid renders aluminium active due to the formation of nitride film on its surface.
    \nAnswer:
    \nFalse.
    \nCorrect statement: Cone. Nitric acid renders aluminium passive due to the formation of oxide film on its surface.<\/p>\n

    Question 29.
    \nAluminium is a powerful reducing agent.
    \nAnswer:
    \nTrue.<\/p>\n

    Question 30.
    \nDuralumin alloy is light, having high tensile strength and corrosion-resistant.
    \nAnswer:
    \nTrue.<\/p>\n

    Question 31.
    \nFe and Al2<\/sub>O3<\/sub> are used in thermite welding.
    \nAnswer:
    \nFalse.
    \nCorrect statement: Al powder and Fe2<\/sub>O3<\/sub> is used in thermite welding.<\/p>\n

    Question 32.
    \nThe chief ore of copper is Ruby copper.
    \nAnswer:
    \nFalse.
    \nCorrect statement: The chief ore of copper is copper pyrite.<\/p>\n

    Question 33.
    \nIron is a lustrous greyish white metal and can be magnetised.
    \nAnswer:
    \nTrue.<\/p>\n

    Question 34.
    \nThe rust has the chemical formula as Fe3<\/sub>O4<\/sub>.
    \nAnswer:
    \nFalse.
    \nCorrect statement: The rust has the chemical formula as Fe2<\/sub>O3<\/sub>. xH2<\/sub>O.<\/p>\n

    V. Assertion and Reason.<\/p>\n

    Question 1.
    \nAssertion (A): Nobel gas is unreactive.
    \nReason (R): They have unstable electronic configuration in their valence shells.
    \n(a) Both (A) and (R) are correct
    \n(b) Both (A) and (R) are not correct
    \n(c) (A) is correct but (R) is wrong
    \n(d) (A) is wrong but (R) is correct.
    \nAnswer:
    \n(c) (A) is correct but (R) is wrong<\/p>\n

    Question 2.
    \nAssertion (A): The nature of bond in NaI molecule is covalent.
    \nReason (R): The electronegativity difference between Na and I is 1.5
    \n(a) Both (A) and (R) are correct
    \n(b) Both (A) and (R) are not correct
    \n(c) (A) is correct but (R) is wrong
    \n(d) (A) is wrong but (R) is correct.
    \nAnswer:
    \n(a) Both (A) and (R) are correct<\/p>\n

    Question 3.
    \nAssertion (A): Haematite ore was purified by Hydraulic method.
    \nReason (R): Haematite is oxide ore.
    \n(a) Both (A) and (R) are correct
    \n(b) Both (A) and (R) are wrong
    \n(c) (A) is correct but (R) is wrong
    \n(d) (A) is wrong but (R) is correct.
    \nAnswer:
    \n(a) Both (A) and (R) are correct
    \nQuestion 4.
    \nAssertion (A): Corundum is a chief ore of aluminium.
    \nReason (R): Molecular formula of Corundum is Al2<\/sub>O3<\/sub>
    \n(a) (A) and (R) are correct, (R) explains the (A)
    \n(b) (A) is correct, (R) is wrong
    \n(c) (A) is wrong, (R) is correct
    \n(d) (A) and (R) are correct, (R) doesn’t explain (A).
    \nAnswer:
    \n(c) (A) is wrong, (R) is correct<\/p>\n

    Question 5.
    \nAssertion (A): The chemical properties of the elements in the same period are not similar.
    \nReason (R): As the electronic configuration changes across the period, the chemical properties of the elements are not similar.
    \n(a) Both (A) and (R) are correct
    \n(b) Both (A) and (R) are not correct
    \n(c) (A) is correct but (R) is wrong
    \n(d) (A) is wrong but (R) is correct.
    \nAnswer:
    \n(a) Both (A) and (R) are correct<\/p>\n

    Question 6.
    \nAssertion (A): Copper, Silver and Gold are used in making coins and jewellery. So they are called coinage metals.
    \nReason (R): These metals release an enormous amount of nuclear energy.
    \n(a) Both (A) and (R) are correct
    \n(b) Both (A) and (R) are wrong
    \n(c) (A) is correct but (R) is wrong
    \n(d) (A) is wrong but (R) is correct.
    \nAnswer:
    \n(c) (A) is correct but (R) is wrong<\/p>\n

    Question 7.
    \nAssertion (A): Metals like Titanium, Chromium, Manganese and Zirconium are called strategic metals!
    \nReason (R): They find their applications in the manufacturing of defence equipment.
    \n(a) Both (A) and (R) are correct
    \n(b) Both (A) and (R) are wrong
    \n(c) (A) is correct but (R) is wrong
    \n(d) (A) is wrong but (R) is correct.
    \nAnswer:
    \n(a) Both (A) and (R) are correct<\/p>\n

    Question 8.
    \nAssertion (A): Gold, Silver and Platinum are the metals that are found in a free state.
    \nReason (R): Those metals have low chemical reactivity and are found in a free state or in the native state.
    \n(a) Both (A) and (R) are wrong
    \n(b) Both (A) and (R) are correct
    \n(c) (A) is correct but (R) is wrong
    \n(d) (A) is wrong but (R) is correct.
    \nAnswer:
    \n(b) Both (A) and (R) are correct<\/p>\n

    Question 9.
    \nAssertion (A): Aluminium occurs in the combined state.
    \nReason (R): It is a reactive metal and so it occurs in combined state.
    \n(a) Both (A) and (R) are correct
    \n(b) Both (A) and (R) are wrong
    \n(c) (A) is correct but (R) is wrong
    \n(d) (A) is wrong but (R) is correct.
    \nAnswer:
    \n(a) Both (A) and (R) are correct<\/p>\n

    Question 10.
    \nAssertion (A): In the aluminothermic process, Iron oxide is reduced to iron by igniting with Aluminium powder.
    \nReason (R): Aluminium is a powerful reducing agent.
    \n(a) Both (A) and (R) are wrong
    \n(b) (A) is correct but (R) is wrong
    \n(c) (A) is wrong but (R) is correct
    \n(d) Both (A) and (R) are correct.
    \nAnswer:
    \n(d) Both (A) and (R) are correct<\/p>\n

    Question 11.
    \nAssertion (A): When iron is dipped in conc.HNO3<\/sub> it becomes chemically inert (or) passive.
    \nReason (R): Iron becomes passive when treated with nitric acid is due to the formation of a layer of iron oxide Fe3<\/sub>O4<\/sub> on its surface.
    \n(a) Both (A) and (R) are correct
    \n(b) (A) is correct but (R) is wrong
    \n(c) (A) is wrong but (R) is correct
    \n(d) Both (A) and (R) are wrong.
    \nAnswer:
    \n(d) Both (A) and (R) are wrong<\/p>\n

    Question 12.
    \nAssertion (A): Duralumin is used in making aircraft, tools and pressure cookers.
    \nReason (R): Duralumin is an alloy that is light, strong, resistant to corrosion.
    \n(a) Both (A) and (R) are wrong
    \n(b) Both (A) and (R) are correct
    \n(c) (A) is correct but (R) is wrong
    \n(d) (A) is wrong but (R) is correct.
    \nAnswer:
    \n(b) Both (A) and (R) are correct<\/p>\n

    Question 13.
    \nAssertion (A): Nickel steel is used in making cables, aircraft parts and propeller.
    \nReason (R): Nickel steel alloy is hard, brittle and polishable.
    \n(a) Both (A) and (R) are correct
    \n(b) Both (A) and (R) are wrong
    \n(c) (A) is correct but (R) is wrong
    \n(d) (A) is wrong but (R) is correct.
    \nAnswer:
    \n(c) (A) is correct but (R) is wrong<\/p>\n

    Question 14.
    \nAssertion (A): Magnesium is used in a sacrificial protection method to prevent corrosion.
    \nReason (R): Magnesium is more reactive than iron. When it is coated on the articles made of steel, it sacrifices itself to protect steel.
    \n(a) Both (A) and (R) are correct
    \n(b) Both (A) and (R) are wrong
    \n(c) (A) is correct but (R) is wrong
    \n(d) (A) is wrong but (R) is correct.
    \nAnswer:
    \n(a) Both (A) and (R) are correct<\/p>\n

    Question 15.
    \nAssertion (A): Electroplating method not only protects but also enhances the metallic appearance.
    \nReason (R): Electroplating is a method of coating one metal with another by passing current.
    \n(a) (A) is right, (R) is wrong
    \n(b) (A) is right, (R) is not relevant
    \n(c) (A) is right, (R) is relevant
    \n(d) Both (A) and (R) are wrong.
    \nAnswer:
    \n(c) (A) is right, (R) is relevant<\/p>\n

    VI. Short Answer Questions.<\/p>\n

    Question 1.
    \nState modern periodic law.
    \nAnswer:
    \nModem periodic law states that the physical and chemical properties of elements are the periodic function of their atomic numbers.<\/p>\n

    Question 2.
    \nWrite the flow chart of the long form of the periodic table.
    \nAnswer:
    \n\"Samacheer<\/p>\n

    Question 3.
    \nThe distance between the adjacent copper atoms in solid copper is 2.56 \u00c5. Calculate what is the metallic radius of Cu?
    \nAnswer:
    \nMetallic radius of copper = \\(\\frac{2.56}{2}\\) = 1.28 \u00c5<\/p>\n

    Question 4.
    \nBriefly write any four characteristics of a group in the periodic table.
    \nAnswer:<\/p>\n

      \n
    • The elements present in a group have the same valency.<\/li>\n
    • The elements present in a group have identical chemical properties.<\/li>\n
    • The physical properties of the elements in the group very gradually.<\/li>\n
    • The atomic radii of die elements present in a group increase downwards.<\/li>\n<\/ul>\n

      Question 5.
      \nWhat is the principle behind Froth floatation?
      \nAnswer:
      \nThis process depends on the preferential wettability of the ore with oil (pine oil) and the gangue particles by water. Lighter ores, such as sulphide ores, are concentrated by this method. Eg: Zinc blende (ZnS).<\/p>\n

      Question 6.
      \nWhat are minerals?
      \nAnswer:
      \nA mineral may be a single compound or a complex mixture of various compounds of metals found in the earth, e.g. Clay Al2<\/sub>O3<\/sub>. 2SiO2<\/sub>. 2H2<\/sub>O is the mineral of Aluminium.<\/p>\n

      Question 7.
      \nWrite the increasing order of radii of the following species.
      \n(a) Na, Na+<\/sup>, Cl, Cl–<\/sup>
      \n(b) Li, Na, K, Rb
      \nAnswer:
      \n(a) Na+<\/sup>, Cl, Na, Cl–<\/sup>
      \n(b) Li, Na, K, Rb<\/p>\n

      Question 8.
      \nDifferentiate ore and mineral.
      \nAnswer:<\/p>\n\n\n\n\n\n\n
      Ore<\/strong><\/td>\nMineral<\/strong><\/td>\n<\/tr>\n
      1. Ores contain a large percentage of metal.<\/td>\n1. Minerals contain a low percentage of metal.<\/td>\n<\/tr>\n
      2. Ores can be used for die extraction of metals on a large scale readily and economically.<\/td>\n2. Metals cannot be extracted easily from minerals.<\/td>\n<\/tr>\n
      3. Bauxite Al2<\/sub>O3<\/sub>. 2H2<\/sub>O is the ore of aluminium.<\/td>\n3. Clay Al2<\/sub>O3<\/sub>.2SiO.2H2<\/sub>O is the mineral of aluminium.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      Question 9.
      \nDefine metallurgy.
      \nAnswer:
      \nThe various steps involved in the extraction of metals from their ores as well as refining of crude metals are collectively known as metallurgy.<\/p>\n

      Question 10.
      \nElements a, b, c and d have the following electronic configurations
      \n(a) ls2<\/sup> 2s\u00b2 2p6<\/sup>
      \n(b) Is\u00b2, 2s\u00b2, 2p6<\/sup>, 3s\u00b2, 3p1<\/sup>
      \n(c) Is\u00b2, 2s\u00b2, 2p6<\/sup>, 3s\u00b2, 3p6<\/sup>
      \n(d) Is\u00b2, 2s\u00b2, Ip1<\/sup>
      \nAnswer:
      \n(a) and (c), (b) and (d). Because the number of valence electrons are the same.<\/p>\n

      Question 11.
      \nWhat is slag? Give an example.
      \nAnswer:
      \nSlag is a fusible product formed when flux reacts with gangue during the extraction of metals.
      \nFlux + gangue \u2192 slag
      \nCaO + SiO2<\/sub> \u2192 CaSiO3<\/sub><\/p>\n

      Question 12.
      \nWhy the electron affinities of noble gases are zero?
      \nAnswer:
      \nNoble gases show no tendency to accept electrons because the outer 5 and p orbitals of noble gases are completely filled. No more electrons can be added to them and hence their electron affinities are zero.<\/p>\n

      Question 13.
      \nWhy does gold, silver and platinum occur in free state?
      \nAnswer:
      \nGold, silver and platinum have low chemical reactivity and so they are found in the free state or in a native state.<\/p>\n

      Question 14.
      \nHow does Aluminium reacts with air?
      \nAnswer:
      \nReaction with air: It is not affected by dry air. On heating at 800\u00b0C, aluminium bums very brightly forming it\u2019s oxide and nitride.
      \n4Al + 3O2<\/sub> \u2192 Al2<\/sub>O3<\/sub>(Aluminium oxide)
      \n2Al + N2<\/sub> \u2192 2 AlN (Aluminium nitride)<\/p>\n

      Question 15.
      \nHow does Aluminium react with caustic soda? Give an equation.
      \nAnswer:
      \nAluminium reacts with caustic soda to give sodium meta aluminate with the liberation of H2<\/sub> gas.
      \n\"Samacheer<\/p>\n

      Question 16.
      \nProve that aluminium is a powerful reducing agent.
      \nAnswer:
      \nAluminium is a powerful reducing agent When a mixture of aluminium powder and iron oxide is ignited, iron oxide is reduced to iron. This process is known as the aluminothermic process.
      \n\"Samacheer<\/p>\n

      Question 17.
      \nWrite a note on Aluminothermic process.
      \nAnswer:
      \nAs reducing agent: Aluminium is a powerful reducing agent. When a mixture of aluminium powder and iron oxide is ignited, the latter is reduced to metal. This process is known as aluminothermic process.
      \nFe2<\/sub>O3<\/sub> + 2Al \u2192 2Fe + Al2<\/sub>O3<\/sub> + heat<\/p>\n

      Question 18.
      \nWhat is the action of heat on copper?
      \nAnswer:
      \nOn heating at different temperatures in the presence of oxygen, copper forms two types of oxides CuO, Cu2<\/sub>O.
      \n\"Samacheer<\/p>\n

      Question 19.
      \nExplain the action of dilute nitric acid with copper.
      \nAnswer:
      \nCopper reacts with dil.HNO3<\/sub> with the liberation of Nitric oxide gas.
      \n\"Samacheer<\/p>\n

      Question 20.
      \nWhat happens when copper is treated with conc.HNO3<\/sub> and with conc.H2<\/sub>SO4<\/sub>?
      \nAnswer:
      \n\"Samacheer<\/p>\n

      Question 21.
      \nWhat do you mean by Ferrous and Non-Ferrous alloys? Given an example for each.
      \nAnswer:
      \nFerrous alloys : Contain iron as a major component.
      \nEg: Stainless steel, Nickel steel<\/p>\n

      Non-Ferrous alloys : These alloys do not contain iron as a major part.
      \nEg: Aluminium alloy, Copper alloy.<\/p>\n

      Question 22.
      \nExplain the action of air with iron.
      \nAnswer:
      \n3Fe + 2O2<\/sub> \u2192 Fe3<\/sub>O4<\/sub> [Magnetic oxide (Black)].<\/p>\n

      Question 23.
      \nWhat are amalgams? How are they prepared?
      \nAnswer:
      \nAn amalgam is an alloy of mercury with another metal.
      \nAmalgams are formed by the metallic bonding with the electrostatic force of attraction between the electrons and the positively charged metal ions.<\/p>\n

      Question 24.
      \nExplain the action of steam with iron.
      \nAnswer:
      \n\"Samacheer<\/p>\n

      Question 25.
      \nMention the types of iron on the basis of carbon content.
      \nAnswer:<\/p>\n\n\n\n\n\n
      Pig iron<\/td>\nIron with 2 – 4.5% carbon<\/td>\n<\/tr>\n
      Wrought iron<\/td>\nIron with < 0.25% carbon<\/td>\n<\/tr>\n
      Steel<\/td>\nIron with 0.25 – 2% carbon<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      Question 26.
      \nWhat is dry corrosion or chemical corrosion?
      \nAnswer:
      \nThe corrosive action in the absence of moisture is called dry corrosion. It is the process of a chemical attack on a metal by corrosive liquids or gases such as O2<\/sub>, N2<\/sub>, SO2<\/sub>, H2<\/sub>S etc… It occurs at high temperature, of all the gases mentioned above O2<\/sub> is the most reactive gas to impart the chemical attack.<\/p>\n

      Question 27.
      \nWhat is an amalgam? Give one example with its use.
      \nAnswer:<\/p>\n

        \n
      • An amalgam is an alloy of mercury with metals such as sodium, gold and silver.<\/li>\n
      • Dental amalgam is an alloy of mercury with silver and tin and it is used in the dental filling.<\/li>\n<\/ul>\n

        Question 28.
        \nExplain sacrificial protection.
        \nAnswer:
        \nMagnesium is more reactive than iron. When it is coated on the articles made of steel, it sacrifices itself to protect steel.<\/p>\n

        Question 29.
        \nDefine corrosion.
        \nAnswer:
        \nCorrosion is defined as the slow and steady destruction of a metal by the environment. It results in the deterioration of the metal to form metal compounds by means of chemical reactions with the environment.
        \n\"Samacheer<\/p>\n

        Question 30.
        \nWhat is the action of Air and moisture on copper?
        \nAnswer:
        \nCopper gets covered with a green layer of basic carbonate in the presence of CO2<\/sub> and moisture.
        \n2 Cu + O2<\/sub> + CO2<\/sub> + H2<\/sub>O \u2192 CUCO3<\/sub>.CU(OH)2<\/sub><\/p>\n

        Question 31.
        \nGive any two uses of aluminium.
        \nAnswer:<\/p>\n

          \n
        • Aluminium metal is a corrosion – resistant and a good conductor of heat. So it is used in making utensils.<\/li>\n
        • Aluminium is used in welding as thermite and a very good reducing agent.<\/li>\n<\/ul>\n

          Question 32.
          \nWhat is the modern periodic table?
          \nAnswer:
          \nThe modem periodic table is a tabular arrangement of elements in rows and columns, highlighting the regular repetition of properties of the elements.<\/p>\n

          Question 33.
          \nExplain the smelting process of iron in the Blast furnace.
          \nAnswer:
          \nThe charge consisting of roasted ore, coke and limestone in the ratio 8 : 4 : 1 is smelted in a blast furnace by introducing it through the cup and cone arrangement at the top.<\/p>\n

          Question 34.
          \nWhat are the periodic properties?
          \nAnswer:
          \nProperties such as atomic radius, ionic radius, ionisation energy, electronegativity, electron affinity, show a regular periodicity and hence they are called periodic properties.<\/p>\n

          Question 35.
          \nDefine Atomic radius.
          \nAnswer:
          \nThe atomic radius of an atom is defined as the distance between the centre of its nucleus and the outermost shell containing the valence electron.<\/p>\n

          Question 36.
          \nWrite the action of dil.HCl and dil.H2<\/sub>SO4<\/sub> with iron.
          \nAnswer:
          \n(i) Fe + 2HCl \u2192 FeCl2<\/sub> + H2<\/sub>\u2191
          \n(ii) Fe + H2<\/sub>SO4<\/sub> \u2192 FeSO4<\/sub> + H2<\/sub>\u2191<\/p>\n

          Question 37.
          \nWhat is a covalent radius?
          \nAnswer:
          \nIt is defined as half the distance between the nuclei of two covalently bonded atoms of the same element in a molecule.<\/p>\n

          Question 38.
          \nDefine Ionisation energy.
          \nAnswer:
          \nIonisation energy is the minimum energy required to remove an electron from a gaseous atom in its ground state to form a cation.<\/p>\n

          Question 39.
          \nWhat is an alloy?
          \nAnswer:
          \nAn alloy is a homogeneous mixture of two or more metals or of one or more metals with certain non-metallic elements. The properties of alloys are often different from the component metals.<\/p>\n

          Question 40.
          \nWhat is Electronegativity?
          \nAnswer:
          \nElectronegativity of an element is the measure of the tendency of its atom to attract the shared pair of electrons towards itself in a covalent bond.<\/p>\n

          Question 41.
          \nWrite the steps involved in metallurgical process.
          \nAnswer:
          \nA metallurgical process involves three main steps as follows:<\/p>\n

            \n
          • Concentration or Separation of the ore: It is the process of removal of impurities from the ore.<\/li>\n
          • Production of the metal: It is the conversion of the ore into metal.<\/li>\n
          • Refining of the metal: It is the process of purification of the metal.<\/li>\n<\/ul>\n

            Question 42.
            \nGive a single term for each of the following:
            \n(i) The process of extracting the ores from the Earth\u2019s crust is called:
            \nAnswer:
            \nMining<\/p>\n

            (ii) The rocky impurities associated with an ore is called:
            \nAnswer:
            \nGangue or matrix<\/p>\n

            (iii) The substance added to the ore to reduce fusion temperature:
            \nAnswer:
            \nFlux<\/p>\n

            (iv) Noble metals occur in this state:
            \nAnswer:
            \nNative<\/p>\n

            Question 43.
            \nHow will you convert copper into copper carbonate?
            \nAnswer:
            \nCopper reacts with oxygen in the presence of CO2<\/sub> and moisture to give copper carbonate.
            \n2Cu + O2<\/sub> + CO2<\/sub> + H2<\/sub>O \u2192 CuCO3<\/sub>. Cu(OH)2<\/sub> (Copper Carbonate).<\/p>\n

            Question 44.
            \nMention the uses of iron.
            \nAnswer:
            \nUses of iron:<\/p>\n

              \n
            1. Pig iron (Iron with 2 – 4.5 % of carbon): It is used in making pipes, stoves, radiators, railings, manhole covers and drain pipes.<\/li>\n
            2. Steel (Iron with < 0.25 % of carbon): It is used in the construction of buildings, machinery, transmission cables and T.V towers and in making alloys.<\/li>\n
            3. Wrought iron (Iron with 0.25 – 2 % of wrought carbon): It is used in making springs, anchors and electromagnets.<\/li>\n<\/ol>\n

              Question 45.
              \nWhat are the chemical properties of metals in terms of<\/p>\n

                \n
              1. valence electrons<\/li>\n
              2. Atomicity.<\/li>\n<\/ol>\n

                Answer:<\/p>\n

                  \n
                1. Valence electrons: Metals usually have 1, 2 or 3 electrons in their outermost shell.<\/li>\n
                2. Atomicity: Metals are usually monoatomic in their vapour state.<\/li>\n<\/ol>\n

                  Question 46.
                  \nWhy alloys are said to solid solutions?
                  \nAnswer:
                  \nAlloys can be considered solid solutions in which the metal with high concentration is solvent and other metals are solute.
                  \nExample: brass is a solid solution of zinc (solute) in copper (solvent).<\/p>\n

                  Question 47.
                  \nWrite a note on Dry corrosion.
                  \nAnswer:<\/p>\n

                    \n
                  • The corrosive action in the absence of moisture is called dry corrosion.<\/li>\n
                  • It is the process of a chemical attack on a metal by corrosive liquids or gases such as O2<\/sub>, N2<\/sub>, SO2<\/sub>, H2<\/sub>S etc. in which O2<\/sub> is more reactive.<\/li>\n
                  • It occurs at high temperature<\/li>\n<\/ul>\n

                    Question 48.
                    \nExplain Wet Corrosion.
                    \nAnswer:<\/p>\n

                      \n
                    • The corrosive action in the presence of moisture is called wet corrosion.<\/li>\n
                    • It occurs as a result of the electrochemical reaction of metal with water or an aqueous solution of salt or acids or bases.<\/li>\n<\/ul>\n

                      Question 49.
                      \nWhat is electroplating?
                      \nAnswer:
                      \nElectroplating is a method of coating one metal over another metal by passing an electric current.<\/p>\n

                      VII. Long Answer Questions.<\/p>\n

                      Question 1.
                      \nExplain the variation of ionisation energy along the group and period.
                      \nAnswer:<\/p>\n

                        \n
                      • As the atomic size decreases from left to right in a period, more energy is required to remove the electrons. So, the ionisation energy increases throughout the period.<\/li>\n
                      • Down the group, the atomic size increases and hence the valence electrons are loosely bound. They require relatively less energy for the removal. Thus, ionisation energy decreases down the group in the periodic table.<\/li>\n<\/ul>\n

                        Question 2.
                        \nExplain the electrolytic refining of copper.
                        \nAnswer:
                        \n(i) Blister copper contains 98% of pure Cu and 2 % of impurities and is purified by electrolytic refining.
                        \nFor electrolytic refining of Cu we use:
                        \nCathode: A thin plate of pure Cu.
                        \nAnode: A block of impure Cu
                        \nElectrolyte: CuSO4<\/sub> + dil H2<\/sub>SO4<\/sub><\/p>\n

                        (ii) When electric current is passed through the electrolytic solution, Pure Cu gets deposited at the cathode and the impurities settle at the bottom of the anode in the form of anode mud.<\/p>\n

                        Question 3.
                        \nExplain Gravity separation method.
                        \nAnswer:
                        \nGravity Separation (or) Hydraulic method:
                        \n1. Principle: The difference in the densities or specific gravities of the ore and the gangue is the main principle behind this method. Oxide ores are purified by this method,
                        \ne.g., Haematite Fe2<\/sub>O3<\/sub> the ore of iron.<\/p>\n

                        2. Method: The ore is poured over a sloping, vibrating corrugated table with grooves and a jet of water is allowed to flow over it. The denser ore particles settle down in the grooves and lighter gangue particles are washed down by the water.<\/p>\n

                        Question 4.
                        \nDiscuss the magnetic separation methods.
                        \nAnswer:
                        \nMagnetic separation method:
                        \nPrinciple: The magnetic properties of the ores from the basis of separation. When either the ore or the gangue is magnetic, this method is employed, e.g., Tinstone SnO2<\/sub>, the ore of tin.
                        \n\"Samacheer
                        \nMethod: The crushed ore is placed over a conveyer belt which rotates around two metal wheels, one of which is magnetic. The magnetic particles are attracted to the magnetic wheel and fall separately apart from the nonmagnetic particles.<\/p>\n

                        Question 5.
                        \nExplain the froth floatation process.
                        \nAnswer:
                        \nFroth floatation Process:
                        \nPrinciple: This process depends on the preferential wettability of the ore with oil (pine oil) and the gangue particles by water. Lighter ores, such as sulphide ores, are concentrated by this method, e.g., Zinc blende (ZnS).
                        \n\"Samacheer
                        \nMethod: The crushed ore is taken in a large tank containing oil and water and agitated with a current of compressed air. The ore is wetted by the oil and gets separated from the gangue in the form of froth. Since the ore is lighter, it comes on the surface with the froth and the impurities are left behind, e.g., Zinc blende (ZnS).<\/p>\n

                        Question 6.
                        \nHow will you extract aluminium from its ore?
                        \nAnswer:
                        \nThe extraction of aluminium from bauxite involves two steps:
                        \n(i) Conversion of bauxite into alumina – Baeyer\u2019s Process
                        \nThe conversion of Bauxite into Alumina involves the following steps:
                        \nBauxite ore is finely ground and heated under pressure with a solution of concentrated caustic soda solution at 150\u00b0 C to obtain sodium metal aluminate.
                        \nOn diluting sodium meta aluminate with water, a precipitate of aluminium hydroxide is formed.
                        \nThe precipitate is filtered, washed, dried and ignited at 1000\u00b0C to get alumina.
                        \n\\(2 \\mathrm{Al}(\\mathrm{OH})_{3} \\stackrel{1000^{\\circ} \\mathrm{C}}{\\longrightarrow} \\mathrm{Al}_{2} \\mathrm{O}_{3}+3 \\mathrm{H}_{2} \\mathrm{O}\\)<\/p>\n

                        (ii) Electrolytic reduction of alumina – Hall\u2019s Process
                        \nAluminium is produced by the electrolytic reduction of fused alumina (Al2<\/sub>O3<\/sub>) in the electrolytic cell.
                        \n\"Samacheer
                        \nCathode: Iron tank linked with graphite
                        \nAnode: A bunch of graphite rods suspended in a molten electrolyte.
                        \nElectrolyte: Pure alumina + molten cryolite + fluorspar (fluorspar lowers the fusion temperature of electrolyte)
                        \nTemperature: 900 – 950\u00b0C
                        \nThe voltage used: 5 – 6 V
                        \nAluminium is deposited at the cathode and oxygen gas is liberated at the anode. Oxygen combines with graphite to form CO2<\/sub>.<\/p>\n

                        Question 7.
                        \nExplain the extraction of copper from copper pyrites.
                        \nAnswer:
                        \nExtraction of copper from copper pyrites involves the following steps:
                        \n(i) The concentration of ore: The ore is crushed and then concentrated by froth floatation process.<\/p>\n

                        (ii) Roasting: The concentrated ore is roasted in excess of air. During the process of roasting, the moisture and volatile impurities are removed. Sulphur, phosphorus, arsenic and antimony are removed as oxides. Copper pyrite is partly converted into sulphides of copper and iron.
                        \n\\(2 \\mathrm{CuFeS}_{2}+\\mathrm{O}_{2} \\rightarrow \\mathrm{Cu}_{2} \\mathrm{S}+2 \\mathrm{FeS}+\\mathrm{SO}_{2} \\uparrow\\)<\/p>\n

                        (iii) Smelting: The roasted ore is mixed with powdered coke and sand and is heated in a blast furnace to obtain matte (Cu2<\/sub>S + FeS) and slag. The slag is removed as waste.<\/p>\n

                        (iv) Bessemerisation: The molten matte is transferred to the Bessemer converter in order to obtain blister copper. Ferrous sulphide from matte is oxidized to ferrous oxide, which is removed as slag using silica.
                        \n\"Samacheer<\/p>\n

                        (v) Refining: Blister copper contains 98% of pure copper and 2% of impurities and is purified A by electrolytic refining. This method is used to get metal of a high degree of purity. For electrolytic refining of copper, we use:
                        \nCathode: A thin plate of pure copper metal.
                        \nAnode: A block of impure copper metal.
                        \nElectrolyte: Copper sulphate solution acidified with sulphuric acid.
                        \nWhen an electric current is passed through the electrolytic solution, pure copper gets deposited at the cathode and the impurities settle at the bottom of the anode in the form of sludge called anode mud.<\/p>\n

                        Question 8.
                        \nExplain the metallurgy of iron.
                        \nAnswer:
                        \nIron is chiefly extracted from haematite ore (Fe2<\/sub>O3<\/sub>):
                        \n(i) Concentration by Gravity Separation: The powdered ore is washed with steam of water. As a result, the lighter sand particles and other impurities are washed away and the heavier ore particles settle down.<\/p>\n

                        (ii) Roasting and Calcination: The concentrated ore is strongly heated in a limited supply of air in a reverberatory furnace. As a result, moisture is driven out and sulphur, arsenic and phosphorus impurities are oxidized off.<\/p>\n

                        (iii) Smelting (in a Blast Furnace): The charge consisting of roasted ore, coke and limestone in the ratio 8 : 4 : 1 is smelted in a blast furnace by introducing it through the cup and cone arrangement at the top. There are three important regions in the furnace.
                        \n\"Samacheer
                        \na. The Lower Region (Combustion Zone):
                        \nThe temperature is at 1500\u00b0C. In this region, coke bums with oxygen to form CO2<\/sub> when the charge comes in contact with a hot blast of air.
                        \n\"Samacheer
                        \nIt is an exothermic reaction since heat is liberated.<\/p>\n

                        b. The Middle Region (Fusion Zone):
                        \nThe temperature prevails at 1000\u00b0C. In this region, CO2<\/sub> is reduced to CO.
                        \n\"Samacheer
                        \nLimestone decomposes to calcium oxide and CO2<\/sub>
                        \n\"Samacheer
                        \nThese two reactions are endothermic due to absorption of heat. Calcium oxide combines with silica to form calcium silicate slag.
                        \nCaO + SiO2<\/sub> \u2192 CaSiO3<\/sub><\/p>\n

                        c. The Upper Region (Reduction Zone): The temperature prevails at 400\u00b0C. In this region carbon monoxide reduces ferric oxide to form a fairly pure spongy iron.
                        \n\\(\\mathrm{Fe}_{2} \\mathrm{O}_{3}+3 \\mathrm{CO} \\stackrel{400^{\\circ} \\mathrm{C}}{\\longrightarrow} 2 \\mathrm{Fe}+3 \\mathrm{CO}_{2}\\)
                        \nThe molten iron is collected at the bottom of the furnace after removing the slag.
                        \nThe iron thus formed is called pig iron. It is remelted and cast into different moulds. This iron is called cast iron.<\/p>\n

                        Question 9.
                        \nExplain the types of alloys.
                        \nAnswer:
                        \nBased on the presence or absence of Iron, alloys can be classified into:
                        \n1. Ferrous alloys: Contain Iron as a major component.
                        \nA few examples of ferrous alloys are Stainless Steel, Nickel Steel etc.<\/p>\n

                        2. Non – ferrous alloys: These alloys do not contain Iron as a major component.
                        \nFor example, Aluminium alloy, Copper alloy etc.
                        \nCopper Alloys (Non – ferrous):<\/p>\n\n\n\n\n\n
                        Alloys<\/td>\nUses<\/td>\n<\/tr>\n
                        Brass (Cu, Zn)<\/td>\nElectrical fittings, medal, decorative items, hardware<\/td>\n<\/tr>\n
                        Bronze (Cu, Sn)<\/td>\nStatues, coins, bells, gongs<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                        Aluminium Alloys (Non – ferrous):<\/p>\n\n\n\n\n\n
                        Alloys<\/td>\nUses<\/td>\n<\/tr>\n
                        Duralumin (Al, Mg, Mn, Cu)<\/td>\nAircraft tools, pressure cookers<\/td>\n<\/tr>\n
                        Magnalium (Al, Mg)<\/td>\nAircraft, scientific instruments<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                        Iron Alloys(Ferrous):<\/p>\n\n\n\n\n\n
                        Alloys<\/td>\nUses<\/td>\n<\/tr>\n
                        Stainless steel (Fe, C, Ni, Cr)<\/td>\nUtensils, cutlery, automobile parts<\/td>\n<\/tr>\n
                        Nickel steel (Fe, C, Ni)<\/td>\nCables, aircraft parts, propeller<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                        VIII. HOT Questions.<\/p>\n

                        Question 1.
                        \nWhat would be the atomic number of the next<\/p>\n

                          \n
                        1. alkali metal<\/li>\n
                        2. alkaline earth metal<\/li>\n
                        3. Halogens<\/li>\n
                        4. inert gas, if discovered in future.<\/li>\n<\/ol>\n

                          Answer:<\/p>\n

                            \n
                          1. Alkali metal: 118 + 1 = 119<\/li>\n
                          2. Alkaline earth metal: 120<\/li>\n
                          3. Halogens: 117<\/li>\n
                          4. Inert gas: 118<\/li>\n<\/ol>\n

                            Question 2.
                            \nExplain the mechanism of rusting?
                            \nAnswer:
                            \nRust is chemically known as hydrated ferric oxide (it is formulated as Fe2<\/sub>O3<\/sub>.xH2<\/sub>O).
                            \nRusting results in the formation of scaling reddish – brown hydrated ferric oxide on the surface of iron and iron-containing materials.
                            \n\"Samacheer<\/p>\n

                            Question 3.
                            \nAll ores are minerals, but ait minerals are not ores. Why?
                            \nAnswer:<\/p>\n

                              \n
                            • The elements or compounds of the metals which occur in nature in the earth’s crust are called minerals whereas ore is a mineral from which the metal is profitably extracted.<\/li>\n
                            • For example, aluminium exists in the two mineral forms, that is clay and bauxite. But aluminium is mainly extracted from bauxite which contains 70 % aluminium oxide. So, bauxite is an ore of aluminium whereas clay is not ore.<\/li>\n
                            • So, all ores are minerals but all minerals need not be ores.<\/li>\n<\/ul>\n

                              Question 4.
                              \nWhy the graphite rods acting as anode in the Hall\u2019s process should be replaced periodically?
                              \nAnswer:
                              \nDuring Hall\u2019s Process, the carbon electrodes get consumed, so they have to be replaced periodically.<\/p>\n

                              Question 5.
                              \nAnionic radius Is higher than the corresponding neutral atom. Give reason.
                              \nAnswer:
                              \nWhen an atom gains one or more electrons it forms an anion. During the formation of anion, the number of orbital electrons becomes greater than the nuclear charge. Hence, the electrons are not strongly attracted by the lesser number of nuclear charges. Hence anionic radius is higher than the corresponding neutral atom.<\/p>\n

                              Question 6.
                              \nA reddish – brown metal A, when exposed to moist air, forms a green layer B. When A is heated at different temperatures in the presence of O2<\/sub>, it forms two types of oxides – C (black) and D (red). Identify A, B, C, D and write the balanced equation.
                              \nAnswer:
                              \n(i) A reddish – brown metal A is a copper (Cu).<\/p>\n

                              (ii) When copper (A) is exposed to moist air it forms a green layer (B) is copper carbonate.
                              \n\"Samacheer
                              \n(iii) When copper is heated at different temperature in the presence of oxygen, it forms two types of oxides CuO and Cu2<\/sub>O. (C and D)
                              \n\"Samacheer<\/p>\n

                              Question 7.
                              \nA silvery – white metal on treatment with NaOH and HCl liberates H2<\/sub> gas to form B and C respectively. The metal A will not react with acid D due to the formation of a passive film on the surface. Hence it is used for transporting acid D. Identify A, B, C, D and support your answer with balanced equations.
                              \nAnswer:
                              \n(i) A silvery – white metal (A) is Aluminium (Al).
                              \n(ii) Aluminium reacts with NaOH to form B which is known as sodium meta aluminate with the liberation of H2<\/sub> gas.
                              \n\"Samacheer
                              \n(iii) Aluminium reacts with HCl to form Aluminium chloride which is known as C with the liberation of H2<\/sub> gas.
                              \n\"Samacheer
                              \n(iv) Aluminium does not react with conc. nitric acid (HNO3<\/sub>) which is known as D, due to the formation of a passive film on the surface.<\/p>\n\n\n\n\n\n\n
                              A<\/td>\nAluminium<\/td>\nAl<\/td>\n<\/tr>\n
                              B<\/td>\nSodium meta aluminate<\/td>\nNaAlO2<\/sub><\/td>\n<\/tr>\n
                              C<\/td>\nAluminium chloride<\/td>\nAlCl3<\/sub><\/td>\n<\/tr>\n
                              D<\/td>\nNitric acid<\/td>\nHNO3<\/sub><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                              Question 8.
                              \nMetal A belongs to period 4 and group 8. A in red hot condition reacts with steam to form B. A reacts with dilute HNO3<\/sub> to give C. A again reacts with conc. H2<\/sub>SO4<\/sub> to give D. Find A, B, C and D with suitable reaction.
                              \nAnswer:
                              \n(i) Metal (A) belongs to period 4 and group 8 is iron (Fe).<\/p>\n

                              (ii) Iron (A) reacts with steam to form magnetic oxide (B)
                              \n\"Samacheer<\/p>\n

                              (iii) Iron (A) reacts with dilute HNO3<\/sub> in cold condition to give ferrous nitrate (C).
                              \n\"Samacheer<\/p>\n

                              (iv) Iron (A) reacts with conc.H2<\/sub>SO4<\/sub> to form Ferric Sulphate (D).
                              \n\"Samacheer<\/p>\n

                              Believing that the Tamilnadu State Board Solutions for Class 10th Science Chapter 8 Periodic Classification of Elements Questions and Answers learning resource will definitely guide you at the time of preparation. For more details about Tamilnadu State Board Class 10th Science Chapter 8 textbook solutions, ask us in the below comments and we\u2019ll revert back to you asap.<\/p>\n","protected":false},"excerpt":{"rendered":"

                              Students who are preparing for the Science exam can download this Tamilnadu State Board Solutions for Class 10th Science Chapter 8 from here for free of cost. These Tamilnadu State Board Textbook Solutions PDF cover all 10th Science Nuclear Physics Book Back Questions and Answers. All these concepts of Chapter 8 Periodic Classification of Elements …<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":"","footnotes":""},"categories":[2],"tags":[],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/samacheerkalviguru.com\/wp-json\/wp\/v2\/posts\/2692"}],"collection":[{"href":"https:\/\/samacheerkalviguru.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/samacheerkalviguru.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/samacheerkalviguru.com\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/samacheerkalviguru.com\/wp-json\/wp\/v2\/comments?post=2692"}],"version-history":[{"count":0,"href":"https:\/\/samacheerkalviguru.com\/wp-json\/wp\/v2\/posts\/2692\/revisions"}],"wp:attachment":[{"href":"https:\/\/samacheerkalviguru.com\/wp-json\/wp\/v2\/media?parent=2692"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/samacheerkalviguru.com\/wp-json\/wp\/v2\/categories?post=2692"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/samacheerkalviguru.com\/wp-json\/wp\/v2\/tags?post=2692"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}