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Metals and Non-metals – NCERT Exercises

Q: How do I solve NCERT Class 10 Science Chapter 3 (Metals and Non-metals) exercise questions for the CBSE board exam?

Solve NCERT Chapter 3 u2014 Metals and Non-metals u2014 exercise questions by first reading the question carefully, writing down the given data, recalling the relevant concepts like metals, non-metals, reactivity series, and applying them step by step. This Part 4 covers every intext and end-of-chapter exercise from the NCERT textbook. Write balanced equations, label diagrams clearly and show each step u2014 CBSE Class 10 board examiners award step marks even if the final answer has a small slip. Practising these solutions strengthens conceptual clarity and builds speed for the board exam.

Q: How many marks does Chapter 3 u2014 Metals and Non-metals u2014 carry in the Class 10 Science CBSE paper?

Chapter 3 u2014 Metals and Non-metals u2014 is part of the Class 10 Science syllabus and typically contributes 5u20139 marks in the CBSE board paper, depending on the annual weightage. Questions are drawn from definitions, reasoning, numerical/descriptive problems and diagrams on topics like metals, non-metals, reactivity series. Solving the NCERT exercises in this part is essential because CBSE directly references NCERT for question design.

🎓 Class 10 Science CBSE Theory Ch 3 — Metals and Non-metals ⏱ ~24 min

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Chapter Summary

Key Takeaways from Chapter 3: Metals and Non-metals

Elements are grouped into metals, non-metals, and metalloids based on their physical and chemical properties.
Metals are generally lustrous, hard, ductile, malleable, sonorous, and good conductors of heat and electricity. Exceptions: Hg (liquid at room T), Na and K (very soft).
Non-metals are dull, brittle, poor conductors, with low MP/BP. Exceptions: iodine (lustrous), graphite (conducts electricity), diamond (very high MP).
Metals + O₂ → basic oxides. Some oxides (Al₂O₃, ZnO) are amphoteric.
Metals react with water/acids to release H₂; the rate depends on the metal's reactivity.
Reactivity series (decreasing): K > Na > Ca > Mg > Al > Zn > Fe > Pb > (H) > Cu > Hg > Ag > Au > Pt.
Metals lose electrons to form cations; non-metals gain them to form anions. Oppositely charged ions form ionic bonds.
Ionic compounds are hard, brittle, high-melting, water-soluble, kerosene-insoluble; conduct electricity only when molten or dissolved.
Metallurgy: crushing → concentration → conversion to oxide (roasting/calcination) → reduction → refining.
Reactive metals → electrolysis; moderate → carbon reduction; least reactive → heating in air.
Thermit reaction (Fe₂O₃ + 2Al → 2Fe + Al₂O₃ + heat) is used for welding rails.
Corrosion: Fe rusts to Fe₂O₃·nH₂O, Ag tarnishes to Ag₂S, Cu develops green CuCO₃·Cu(OH)₂.
Prevention: painting, galvanising (Zn), anodising (Al), alloying (stainless steel).

Keywords / Glossary

Metal

Non-metal

Metalloid

Malleability

Ductility

Sonorous

Lustre

Amphoteric oxide

Anodising

Reactivity series

Displacement reaction

Cation

Anion

Ionic bond

Crystal lattice

Mineral

Ore

Gangue

Metallurgy

Roasting

Calcination

Reduction

Electrolytic refining

Thermit reaction

Corrosion

Rusting

Galvanising

Alloy

Stainless steel

Amalgam

Brass / Bronze / Solder

NCERT Exercises — Complete Solutions

1Which of the following pairs will give displacement reactions?

(a) NaCl solution and copper metal
(b) MgCl₂ solution and aluminium metal
(c) FeSO₄ solution and silver metal
(d) AgNO₃ solution and copper metal

Only (d) AgNO₃ solution and copper metal gives displacement, because Cu is more reactive than Ag: Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag. In (a) Cu is less reactive than Na; in (b) Al is less reactive than Mg; in (c) Ag is less reactive than Fe — none of these react.

2Which of the following methods is suitable for preventing an iron frying pan from rusting?

(a) applying grease
(b) applying paint
(c) applying a coating of zinc
(d) all of the above

(c) Applying a coating of zinc (galvanising). Grease and paint would burn/peel off when the pan is used on a stove. Galvanising is permanent and food-safe.

3An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be:

(a) calcium
(b) carbon
(c) silicon
(d) iron

(a) Calcium. CaO is ionic, has a very high MP, and reacts with water to form Ca(OH)₂. Carbon and silicon oxides are covalent and don't behave this way; Fe₂O₃ is insoluble in water.

4Food cans are coated with tin and not with zinc because:

(a) zinc is costlier than tin
(b) zinc has a higher MP than tin
(c) zinc is more reactive than tin
(d) zinc is less reactive than tin

(c) Zinc is more reactive than tin. Zn would react with weak acids in food (fruit juice, pickles) and contaminate the food, whereas Sn is inert enough to be food-safe.

5You are given a hammer, a battery, a bulb, wires and a switch.
(a) How could you use them to distinguish between metals and non-metals?
(b) Assess the usefulness of these tests in distinguishing metals from non-metals.

(a) Hammer test: hit the sample. If it flattens into a sheet → metal (malleable). If it breaks into pieces → non-metal (brittle).
Electrical circuit: connect the sample in a circuit with battery, wires, switch and bulb. If the bulb glows → conductor (metal). If it doesn't → non-conductor (non-metal).
(b) These tests work for most cases but have exceptions: mercury is a liquid metal and cannot be hammered; graphite is a non-metal that conducts electricity; iodine is a non-metal yet lustrous. A single test may mislead — using both together makes identification more reliable.

6What are amphoteric oxides? Give two examples.

Oxides that react with both acids and bases to produce salt and water are called amphoteric oxides. Examples: Al₂O₃ and ZnO.

Al₂O₃ + 6HCl → 2AlCl₃ + 3H₂O

Al₂O₃ + 2NaOH → 2NaAlO₂ + H₂O

7Name two metals which will displace hydrogen from dilute acids, and two metals which will not.

Will displace H₂: Zinc and Magnesium (both above H in the activity series).
Will NOT displace H₂: Copper and Silver (both below H).

8In the electrolytic refining of a metal M, what would you take as the anode, cathode and the electrolyte?

Anode: an impure block of metal M.
Cathode: a thin strip of pure M.
Electrolyte: an aqueous solution of a salt of M (for example MSO₄).
On passing current, Mⁿ⁺ ions migrate to the cathode and deposit as pure metal; impurities fall as "anode mud" beneath the anode.

9Pragya tested the solubility of three different substances at different temperatures and collected the data: (a) sulphur powder does not dissolve in water but dissolves in carbon disulphide. (b) common salt dissolves in water. Explain her observations.

Sulphur is a non-metal forming covalent molecules; it dissolves in non-polar solvents (CS₂) and is insoluble in polar water. Common salt (NaCl) is an ionic compound: polar water molecules surround and separate Na⁺ and Cl⁻ ions, so it dissolves freely in water but not in non-polar solvents.

10What would you observe when zinc is added to a solution of iron(II) sulphate? Write the reaction.

Zn is more reactive than Fe, so it displaces Fe. The pale-green colour of FeSO₄ fades (to colourless ZnSO₄) and a grey deposit of Fe appears on the Zn strip.

\(\text{Zn}(s) + \text{FeSO}_4(aq) \rightarrow \text{ZnSO}_4(aq) + \text{Fe}(s)\)

11Write the electron-dot structures for sodium, oxygen and magnesium. Show the formation of Na₂O and MgO by the transfer of electrons.

Na (2,8,1): one dot outside; O (2,6): six dots; Mg (2,8,2): two dots.
Na₂O: Two Na atoms each give one electron to O: 2Na + O → 2Na⁺ + O²⁻ → Na₂O.
MgO: Mg gives two electrons to O: Mg + O → Mg²⁺ + O²⁻ → MgO.

4Na + O₂ → 2Na₂O 2Mg + O₂ → 2MgO

12Why do ionic compounds have high melting points?

In an ionic compound the cations and anions are held together by strong electrostatic forces in a rigid three-dimensional lattice. A large amount of heat energy is required to overcome these strong interionic forces and separate the ions, so the melting (and boiling) points are correspondingly high.

13Define: (a) mineral (b) ore (c) gangue.

(a) Mineral: a naturally occurring substance of definite chemical composition in which a metal or its compound is found.
(b) Ore: a mineral from which the metal can be extracted conveniently and profitably.
(c) Gangue: the earthy and siliceous impurities (soil, sand, rocks) associated with an ore, which must be removed during concentration.

14Name two metals which are found in nature in the free state.

Gold (Au) and Platinum (Pt) — both are noble metals with very low reactivity. Silver is sometimes also found native.

15What chemical process is used for obtaining a metal from its oxide?

The metal oxide is reduced to the metal. The method depends on reactivity:

Highly reactive metals (K, Na, Ca, Mg, Al) — electrolytic reduction of the molten oxide/chloride.
Moderately reactive metals (Zn, Fe, Pb, Cu) — reduction of oxide with coke (carbon).
Less reactive metals (Hg, Ag) — simple heating of the ore in air.

16Metallic oxides of zinc, magnesium and copper were heated with the following metals:
Mg with ZnO; Zn with MgO; Mg with CuO; Cu with ZnO. In which cases will you find displacement reactions taking place?

Reactivity order: Mg > Zn > Cu.

Pair	Reaction?
Mg + ZnO	Yes — Mg displaces Zn: Mg + ZnO → MgO + Zn
Zn + MgO	No — Zn less reactive than Mg
Mg + CuO	Yes — Mg + CuO → MgO + Cu
Cu + ZnO	No — Cu less reactive than Zn

17Which metals do not corrode easily?

The noble metals — gold (Au), platinum (Pt), and silver (Ag) — do not corrode easily because they are the least reactive metals and resist reaction with air, moisture and acids.

18What are alloys?

An alloy is a homogeneous mixture of two or more metals, or of a metal with a small quantity of a non-metal (such as carbon). Alloys have improved properties over pure metals.

Brass = Cu + Zn — utensils, decorations
Bronze = Cu + Sn — statues, coins
Solder = Pb + Sn — low melting point, used for joining wires
Stainless steel = Fe + C + Cr + Ni — does not rust

19Sodium is kept immersed in kerosene oil. Copper is not kept immersed. Why?

Sodium is extremely reactive — on exposure to air it reacts with O₂ and moisture, and the heat of reaction can set it on fire. Kerosene cuts off air and moisture, preventing this. Copper, on the other hand, is very unreactive; at ordinary temperature it does not react with air or water noticeably, so no special storage is needed.

20Write equations for: (a) steam + iron, (b) calcium + water, (c) potassium + water.

(a) \(3\text{Fe}(s) + 4\text{H}_2\text{O}(g) \xrightarrow{\Delta} \text{Fe}_3\text{O}_4(s) + 4\text{H}_2(g)\)

(b) \(\text{Ca}(s) + 2\text{H}_2\text{O}(l) \rightarrow \text{Ca(OH)}_2(aq) + \text{H}_2(g)\)

21Samples of four metals A, B, C, D were taken and added to four different solutions. Results are in the table:
A + FeSO₄: no reaction; A + CuSO₄: no reaction; A + ZnSO₄: no reaction; A + AgNO₃: no reaction.
B + FeSO₄: no reaction; B + CuSO₄: brown deposit; B + ZnSO₄: no reaction; B + AgNO₃: grey deposit.
C + FeSO₄: grey deposit; C + CuSO₄: brown deposit; C + ZnSO₄: no reaction; C + AgNO₃: grey deposit.
D + FeSO₄: grey deposit; D + CuSO₄: brown deposit; D + ZnSO₄: grey deposit; D + AgNO₃: grey deposit.
(i) Arrange A, B, C, D in decreasing order of reactivity. (ii) What would happen if B is added to CuSO₄? (iii) Which is the least reactive metal?

A doesn't displace any metal — least reactive.
B displaces only Cu and Ag (not Fe or Zn) — so more reactive than Cu and Ag, less than Fe and Zn.
C displaces Cu, Ag and Fe (but not Zn) — more reactive than Fe, less than Zn.
D displaces all of Cu, Ag, Fe, and Zn — most reactive.
(i) Decreasing reactivity: D > C > B > A.
(ii) B + CuSO₄ → BSO₄ + Cu (brown copper deposits on B, blue colour fades).
(iii) A is the least reactive.

22Which gas is evolved when dilute hydrochloric acid is added to a reactive metal? Write its chemical reaction when iron reacts with dilute HCl.

Hydrogen gas (H₂) is evolved; it can be identified by the familiar "pop" test with a burning match.

\(\text{Fe}(s) + 2\text{HCl}(aq) \rightarrow \text{FeCl}_2(aq) + \text{H}_2(g)\uparrow\)

23What would you observe when you drop (i) a few pieces of aluminium in CuCl₂ solution, and (ii) copper wire in FeSO₄ solution?

(i) Al is more reactive than Cu. The blue CuCl₂ solution slowly fades (to colourless AlCl₃) and a reddish-brown Cu deposit forms on Al.

\(2\text{Al} + 3\text{CuCl}_2 \rightarrow 2\text{AlCl}_3 + 3\text{Cu}\)

(ii) No reaction. Cu is less reactive than Fe and cannot displace it.

24What type of oxides are formed when non-metals combine with oxygen?

Non-metals form acidic oxides (or neutral oxides for a few). For example, CO₂, SO₂ and SO₃ dissolve in water to form the acids H₂CO₃, H₂SO₃, H₂SO₄ respectively. Oxides like CO, NO, N₂O are neutral.

25Give reasons: (a) Platinum, gold and silver are used to make jewellery. (b) Sodium, potassium and lithium are stored under oil. (c) Aluminium is a highly reactive metal, yet it is used to make utensils for cooking. (d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction.

(a) Pt, Au, Ag are very unreactive, do not corrode or tarnish easily, are highly lustrous and malleable — ideal aesthetic properties for jewellery.
(b) Na, K, Li are so reactive they catch fire on exposure to air and moisture. Kerosene oil keeps them isolated from both.
(c) Al, though reactive, develops a thin, invisible but tough layer of Al₂O₃ on its surface which prevents further reaction. This makes aluminium safe for cooking vessels.
(d) Metal oxides are much easier to reduce to the metal (using carbon or electrolysis) than sulphides or carbonates. So sulphides are roasted and carbonates calcined to convert them into oxides before reduction.

26You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.

The green tarnish on copper vessels is basic copper carbonate, Cu(OH)₂·CuCO₃. Lemon and tamarind juice contain weak acids (citric acid, tartaric acid) which neutralise this basic tarnish, dissolving it and exposing the shiny copper beneath.

27Differentiate between metal and non-metal on the basis of their chemical properties.

Property	Metals	Non-metals
Reaction with O₂	Form basic oxides (some amphoteric)	Form acidic/neutral oxides
Reaction with H₂O	Reactive ones release H₂	Generally do not react
Reaction with acids	Release H₂ (above H in series)	Do not displace H₂
Electron behaviour	Lose e⁻ → cations (electropositive)	Gain e⁻ → anions (electronegative)
Nature of chlorides	Ionic, conduct in molten state	Covalent, don't conduct

28A man went door to door posing as a goldsmith. He promised to bring back the glitter on old and dull gold jewellery. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new, but their weight was found to be reduced drastically. What chemistry was at work?

The solution was aqua regia (a 3:1 mixture of concentrated HCl and concentrated HNO₃) — one of the very few reagents that dissolves gold. While dipping the bangles, some gold went into the solution as a soluble chloro-complex, reducing the bangles' weight. The cheat later recovered the dissolved gold for himself. The bangles did look shinier because the acids also stripped off oxidation/tarnish from the surface.

29Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).

Copper does not react with cold or hot water (it lies below H in the activity series), so hot water tanks made of copper last a long time. Iron, in contrast, reacts with hot water/steam (3Fe + 4H₂O → Fe₃O₄ + 4H₂), and steel would slowly rust away, contaminating the water and springing leaks.

Frequently Asked Questions — NCERT Exercises & Intext Questions

How do I solve NCERT Class 10 Science Chapter 3 (Metals and Non-metals) exercise questions for the CBSE board exam?

Solve NCERT Chapter 3 — Metals and Non-metals — exercise questions by first reading the question carefully, writing down the given data, recalling the relevant concepts like metals, non-metals, reactivity series, and applying them step by step. This Part 4 covers every intext and end-of-chapter exercise from the NCERT textbook. Write balanced equations, label diagrams clearly and show each step — CBSE Class 10 board examiners award step marks even if the final answer has a small slip. Practising these solutions strengthens conceptual clarity and builds speed for the board exam.

Are the NCERT intext questions from Metals and Non-metals important for the Class 10 board exam?

Yes, NCERT intext questions for Chapter 3 Metals and Non-metals are highly important for the CBSE Class 10 Science board exam. Many board questions are directly lifted or only slightly modified from these intext questions, and they test the foundational concepts — metals, non-metals, reactivity series — that chapter-end questions build on. Attempt every intext question first, then move on to the exercises. This practice ensures complete NCERT coverage, which is the CBSE exam's primary source.

What types of questions from Metals and Non-metals are asked in the CBSE Class 10 Science board exam?

The CBSE Class 10 board paper asks a mix of question types from Metals and Non-metals: 1-mark MCQ and assertion-reason, 2-mark short answers, 3-mark explanations, 5-mark long answers with diagrams or derivations, and 4-mark competency-based / case-study questions. These test understanding of metals, non-metals, reactivity series, metallurgy. Practising every NCERT exercise and intext question prepares you to answer all of these formats with confidence.

How many marks does Chapter 3 — Metals and Non-metals — carry in the Class 10 Science CBSE paper?

Chapter 3 — Metals and Non-metals — is part of the Class 10 Science syllabus and typically contributes 5–9 marks in the CBSE board paper, depending on the annual weightage. Questions are drawn from definitions, reasoning, numerical/descriptive problems and diagrams on topics like metals, non-metals, reactivity series. Solving the NCERT exercises in this part is essential because CBSE directly references NCERT for question design.

Where can I find step-by-step NCERT solutions for Chapter 3 Metals and Non-metals Class 10 Science?

You can find complete, step-by-step NCERT solutions for Chapter 3 Metals and Non-metals Class 10 Science on MyAiSchool. Every intext and end-of-chapter exercise question is solved with full working, labelled diagrams and CBSE-aligned mark distribution. Solutions highlight key points about metals, non-metals, reactivity series that examiners look for. This makes revision quick and exam-focused for Class 10 CBSE board students.

What is the best way to revise Metals and Non-metals before the Class 10 Science board exam?

The best way to revise Metals and Non-metals for the CBSE Class 10 Science board exam is a three-pass approach. First pass: skim the chapter and note down key terms like metals, non-metals, reactivity series in a one-page mind map. Second pass: solve every NCERT intext and exercise question without looking at the solution, then self-check. Third pass: attempt previous CBSE board questions and competency-based questions under timed conditions. This structured revision secures full marks for this chapter.

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