Chapter 3: Metals and Non-metals

Important questions — the ones the board asked most (20)

1. Q1Case-based5 marksAsked: 2026

   Read the following passage and answer the questions given below : Most of metals occur in combined state in form of ores. Carbonate ores are converted into oxides by calcination and sulphide ores by roasting. Oxides are reduced with suitable reducing agent like carbon to get free metal. Highly reactive metals like - Al, Mg are also used as reducing agents to obtain metal from their oxides. Most reactive metals are obtained by electrolytic reduction of their molten ores. Alloying is a very good method of improving the properties of a metal. We can get desired properties by this method. The electrical conductivity and melting point of an alloy is less than that of pure metals. (a) Why carbonate or sulphide ores are converted to oxides before extraction of metal from it ? (b) Write a reaction in which Aluminium is used as a reducing agent to obtain metal from its oxide. (c) (i) How is copper obtained from its ore (Cu2S) ? Give equations of the reactions. OR (c) (ii) (I) Why highly reactive metals cannot be obtained from their oxides by using carbon as a reducing agent ? (II) Why solder, an alloy of lead and tin, is used for welding electrical wires together ?

   

   Medha Ma’am

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   Model answer · extraction of metals, reduction methods

   1. 1.(a) It is easier to obtain a metal from its oxide (by reduction, e.g. with carbon) than from its sulphide or carbonate, so these ores are first converted into oxides.1 mark
   2. 2.(b) Thermit reaction: Fe₂O₃ + 2Al → 2Fe + Al₂O₃ + heat.1 mark
   3. 3.(c)(i) Cu₂S is heated in air (roasting): 2Cu₂S + 3O₂ → 2Cu₂O + 2SO₂. OR (c)(ii)(I) Highly reactive metals such as sodium, magnesium and aluminium have more affinity for oxygen than carbon has, so carbon cannot reduce their oxides.1.5 marks
   4. 4.The Cu₂O formed reacts with the remaining Cu₂S to give copper: 2Cu₂O + Cu₂S → 6Cu + SO₂. OR (c)(ii)(II) Solder has a low melting point, so it melts easily and joins electric wires together.1.5 marks

   Marks split from a structure derived from past papers (checked twice); not CBSE’s official scheme

2. Q2Case-based5 marksAsked: 2026

   Read the following passage and answer the questions that follow : An electrochemical process is used for refining metals by selectively dissolving and depositing them through electrolysis. Electrolytic refining is used for metals like Copper, Zinc, Tin, Nickel, Silver and Gold. (a) Define anode mud. (b) In electrolytic refining of copper, name the anode and the cathode. (c) (i) With the help of chemical equations, show the extraction of copper from its ore Cu2S. OR (c) (ii) Draw a neat and labelled diagram showing electrolytic refining of copper.

   

   Medha Ma’am

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   Model answer · electrolytic refining, extraction of copper

   1. 1.(a) Anode mud is the insoluble impurities from the impure anode that settle at the bottom, below the anode, during electrolytic refining; it often contains silver and gold.1 mark
   2. 2.(b) The anode is a thick block of impure copper.1 mark
   3. 3.The cathode is a thin strip of pure copper.1 mark
   4. 4.(c)(i) Cu₂S is roasted in air: 2Cu₂S + 3O₂ → (heat) 2Cu₂O + 2SO₂. OR (c)(ii) The diagram shows a tank of acidified copper sulphate solution with the anode and cathode dipped in it and connected to a battery.1 mark
   5. 5.The Cu₂O reacts with the remaining Cu₂S: 2Cu₂O + Cu₂S → (heat) 6Cu + SO₂. OR (c)(ii) Labels: impure copper anode (+), pure copper cathode (−), acidified CuSO₄ solution (electrolyte), anode mud.1 mark

   Diagram: Draw a rectangular electrolytic cell containing a solution of acidified copper sulphate as the electrolyte, with a thick block labelled 'Impure copper (Anode)' connected to the positive terminal of a battery and a thin strip labelled 'Pure copper (Cathode)' connected to the negative terminal, with 'Anode mud' shown settling at the bottom of the anode.

   Marks split from a structure derived from past papers (checked twice); not CBSE’s official scheme

3. Q3Long answer5 marksAsked: 2026

   Answer any one out of the two options (A) or (B) : (A) (i) Give reason for the following : (I) Melting and boiling points of ionic compounds are generally high. (II) An alloy of lead and tin solder is used for welding electrical wires together. (III) Carbon cannot reduce the oxides of Na or Mg. (ii) The reaction of aluminium with compound 'X' is used for joining railway tracks : (I) Identify compound 'X'. (II) Write the name of the reaction. (III) Write the balanced chemical equation for the reaction of compound 'X' with aluminium. OR (B) (i) Write balanced chemical equation when : (I) a mixture of Cu2O and Cu2S is heated. (II) ZnS is heated in the presence of oxygen. (ii) Give reason for the following : (I) Wires carrying electricity in our homes are coated with PVC. (II) Copper is used to make hot water tanks and not steel. (iii) Show the formation of the ionic compound CaO by the electron dot structure. [Atomic number : Ca = 20, O = 8]

   

   Medha Ma’am

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   Model answer · Reasons and thermit reaction

   1. 1.(A) (i) (I) Ionic compounds have generally high melting and boiling points because there is a strong inter-ionic attraction, which is the electrostatic force of attraction between the oppositely charged ions. A considerable amount of energy is required to break this strong inter-ionic attraction.1 mark
   2. 2.(II) Solder is an alloy of lead and tin. An alloy is a homogeneous mixture of two or more metals. Solder is used for welding electrical wires together because solder has a low melting point, so it melts easily and joins the wires.1 mark
   3. 3.(III) Carbon cannot reduce the oxides of Na or Mg because Na and Mg are very reactive metals high up in the reactivity series, and they have more affinity for oxygen than carbon.1 mark
   4. 4.(ii) (I) Compound 'X' is Fe2O3, that is, iron(III) oxide.0.5 marks
   5. 5.(II) The reaction is called the thermit reaction.0.5 marks
   6. 6.(III) Balanced chemical equation: Fe2O3(s) + 2Al(s) → 2Fe(l) + Al2O3(s) + Heat This reaction gives off so much heat that the iron forms in the molten state, and this molten iron joins the railway tracks.1 mark

   • For melting points, write "a considerable amount of energy is required to break strong inter-ionic attraction".
   • For carbon and Na or Mg, write that these metals "have more affinity for oxygen than carbon".
   • Balance the thermit equation with 2Al and 2Fe, and write the states and "+ Heat".

   Marks split as in the board’s published marking scheme

4. Q4Long answer5 marksAsked: 2025

   (a) (i) Consider the following metals : K, Ca, Al, Cu, Ag, Fe Select from the above metals, a metal which I. does not react with oxygen even at high temperature. II. reacts with oxygen at ordinary temperature and forms a protective oxide layer which prevents the metal from further oxidation. III. catches fire when kept in the open. IV. does not burn in oxygen but the hot metal is coated with a black coloured oxide layer. (ii) What are amphoteric oxides ? With the help of balanced chemical equations show that aluminium oxide is an amphoteric oxide. (iii) What are alkalis ? Give one example. OR (b) (i) With the help of balanced chemical equations state the process of extracting (I) mercury from its ore called cinnabar, and (II) copper from its sulphide ore. (ii) Silver and copper articles slowly lose their shiny surfaces when exposed to air. Name the compounds formed on (I) silver articles, and (II) copper articles in the form of coating.

   How the model answer begins

   1. (a) (i) I. Silver (Ag) does not react with oxygen even at high temperatures.

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5. Q5Case-based4 marksAsked: 2023

   Almost all metals combine with oxygen to form metal oxides. Metal oxides are generally basic in nature. But some metal oxides show both basic as well as acidic behaviour. Different metals show different reactivities towards oxygen. Some react vigorously while some do not react at all. (a) What happens when copper is heated in air ? (Give the equation of the reaction involved). (b) Why are some metal oxides categorized as amphoteric ? Give one example. (c) Complete the following equations : (i) Na2O(s) + H2O(l) -> (ii) Al2O3 + 2 NaOH ->

   How the model answer begins

   1. When copper is heated in air, it combines with oxygen to form copper(II) oxide, which is a black oxide. The hot metal is coated with this black coloured layer of copper(II) oxide. The equation for this reaction is: 2Cu…

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6. Q6Case-based4 marksAsked: 2025

   37. Many pure metals like copper, iron and gold are very soft and as such are considered unsuitable for certain uses. Metallic objects around us such as cooking utensils, statues, ornaments, guns etc. are actually not made up of pure metals. Instead of pure metals, alloys are used in the design of most of the useful objects. Making alloys enhances the basic properties of a metal which is the primary constituent (metal) of an alloy. (I) How does electrical conductivity and melting point of a metal change when it is converted to its alloy by mixing a small amount of an element in it ? (II) Name an alloy used for welding two wires together in an electric circuit. Write its major constituents. (III) (a) What is an alloy ? How is brass (an alloy) made ? OR (III) (b) What is stainless steel ? How is it made ? Mention one important property of it which makes it more useful than its base metal for cooking utensils.

   How the model answer begins

   1. When a small amount of another element is added to a metal, both its electrical conductivity and melting point decrease.

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7. Q7Case-based4 marksAsked: 2025

   Many pure metals like copper, iron and gold are very soft and as such are considered unsuitable for certain uses. Metallic objects around us such as cooking utensils, statues, ornaments, guns etc. are actually not made up of pure metals. Instead of pure metals, alloys are used in the design of most of the useful objects. Making alloys enhances the basic properties of a metal which is the primary constituent (metal) of an alloy. (I) How does electrical conductivity and melting point of a metal change when it is converted to its alloy by mixing a small amount of an element in it ? (II) Name an alloy used for welding two wires together in an electric circuit. Write its major constituents. (III) (a) What are alloys ? How is ‘Brass’ (an alloy) prepared ? OR (III) (b) What is stainless steel ? How is it prepared ? Mention one important property of it which makes it more useful for cooking utensils as compared to its base metal.

   How the model answer begins

   1. When a small amount of another element is added to a metal to form an alloy, the electrical conductivity of the metal decreases. For example, brass, an alloy of copper and zinc, and bronze, an alloy of copper and tin,…

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8. Q8Case-based4 marksAsked: 2025

   37. Many pure metals like copper, iron and gold are very soft and as such are considered unsuitable for certain uses. Metallic objects around us such as cooking utensils, statues, ornaments, guns etc. are actually not made up of pure metals. Instead of pure metals, alloys are used in the design of most of the useful objects. Making alloys enhances the basic properties of a metal which is the primary constituent (metal) of an alloy. (I) How does electrical conductivity and melting point of a metal change when it is converted to its alloy by mixing a small amount of an element in it ? (II) Name an alloy used for welding two wires together in an electric circuit. Write its major constituents. (III) (a) What are alloys ? How is 'Brass' (an alloy) prepared ? OR (III) (b) What is stainless steel ? How is it prepared ? Write one important property which makes it more useful in making cooking utensils as compared to its primary metal.

   How the model answer begins

   1. (I) Adding a small amount of another element lowers the electrical conductivity.

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9. Q9Case-based4 marksAsked: 2024

   37. The metals produced by various reduction processes are not very pure. They contain impurities, which must be removed to obtain pure metals. The most widely used method for refining impure metals is electrolytic refining. (i) What is the cathode and anode made of in the refining of copper by this process ? (ii) Name the solution used in the above process and write its formula. (iii) (A) How copper gets refined when electric current is passed in the electrolytic cell ? OR (iii) (B) You have two beakers ‘A’ and ‘B’ containing copper sulphate solution. What would you observe after about 2 hours if you dip a strip of zinc in beaker ‘A’ and a strip of silver in beaker ‘B’? Give reason for your observations in each case.

   How the model answer begins

   1. (i) In the electrolytic refining of copper, the cathode is made of pure copper: a thin strip of pure copper is used as the cathode.

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10. Q10Case-based4 marksAsked: 2024

    Three samples of metals magnesium, aluminium and iron were taken and their surfaces were rubbed with sand paper. Thereafter, these samples were put in separate test tubes, containing dilute hydrochloric acid. Thermometers were suspended in each test tube in such a way that their bulbs were immersed in the acid. The rate of bubble formation was observed. The above activity was repeated with dilute nitric acid and the observations were recorded. Answer the following questions : (a) When the activity was performed with dilute hydrochloric acid, in which test tube was the rate of bubble formation the fastest and the thermometer showed the highest temperature ? (b) Which metal did not react with dilute hydrochloric acid ? Give reason. (c) (i) When a metal reacts with dilute nitric acid, why is hydrogen gas not evolved ? Write the names of the final products formed in this reaction. OR (c) (ii) Write the name of the type of reaction on the basis of which the reactivity of metals is determined. You have two metals X and Y. How will you ensure which of these is more reactive than the other ?

11. Q11Case-based4 marksAsked: 2023

    The melting points and boiling points of some ionic compounds are given below : Compound | Melting Point (K) | Boiling Point (K) NaCl | 1074 | 1686 LiCl | 887 | 1600 CaCl2 | 1045 | 1900 CaO | 2850 | 3120 MgCl2 | 981 | 1685 These compounds are termed ionic because they are formed by the transfer of electrons from a metal to a non-metal. The electron transfer in such compounds is controlled by the electronic configuration of the elements involved. Every element tends to attain a completely filled valence shell of its nearest noble gas or a stable octet. (i) Show the electron transfer in the formation of magnesium chloride. (ii) List two properties of ionic compounds other than their high melting and boiling points. (iii) (A) While forming an ionic compound say sodium chloride how does sodium atom attain its stable configuration ? OR (iii) (B) Give reasons : (i) Why do ionic compounds in the solid state not conduct electricity ? (ii) What happens at the cathode when electricity is passed through an aqueous solution of sodium chloride ?

    How the model answer begins

    1. (i) The magnesium atom (2, 8, 2) loses its two valence electrons: Mg → Mg²⁺ + 2e⁻.

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12. Q12Case-based4 marksAsked: 2026

    Read the following passage and answer the questions given below : Most of metals occur in combined state in form of ores. Carbonate ores are converted into oxides by calcination and sulphide ores by roasting. Oxides are reduced with suitable reducing agent like carbon to get free metal. Highly reactive metals like - Al, Mg are also used as reducing agents to obtain metal from their oxides. Most reactive metals are obtained by electrolytic reduction of their molten ores. Alloying is a very good method of improving the properties of a metal. We can get desired properties by this method. The electrical conductivity and melting point of an alloy is less than that of pure metals. (a) Why carbonate or sulphide ores are converted into oxides before extraction of metal from it? (b) Write a reaction in which Aluminium is used as a reducing agent to obtain metal from its oxide. (c) (i) How is copper obtained from its ore (Cu2S)? Give equations of the reactions. (ii) Why highly reactive metals cannot be obtained from their oxides by using carbon as a reducing agent? (iii) Why solder, an alloy of lead and tin, is used for welding of electrical wires?

    How the model answer begins

    1. Carbonate or sulphide ores are converted into oxides before extraction of metal because it is easier to obtain a metal from its oxide, as compared to its sulphides and carbonates. The sulphide ores are converted into…

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13. Q13Case-based4 marksAsked: 2023

    [passage] (a) Name an ore of Mercury and state the form in which Mercury is present in it. (1) (b) What happens to zinc carbonate when it is heated strongly in a limited supply of air ? (1) (c) The reaction of a metal A with Fe2O3 is highly exothermic and is used to join railway tracks. (I) Identify the metal A and name the reaction taking place. (II) Write the chemical equation for the reaction of metal A with Fe2O3. (2) OR (c) We cannot use carbon to obtain sodium from sodium oxide. Why ? State the reactions taking place at cathode and anode during electrolytic reduction of sodium chloride. (2)

14. Q14Short answer3 marksAsked: 2024

    Draw a labelled diagram to show electrolytic refining of copper. State what happens when electric current is passed through the electrolyte taken in this case.

    How the model answer begins

    1. Diagram: a tank filled with the electrolyte, with two electrodes dipped in it. The electrodes are joined by wires to a source of electric current so that current can pass through the electrolyte.

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15. Q15Short answer3 marksAsked: 2026

    Attempt either option (A) or (B). (A) (i) Which method will be used to convert each of them to their respective metal oxides ? (a) Carbonate ore (b) Sulphide ore (ii) Write a chemical reaction to illustrate the use of aluminium for joining cracked railway tracks. (iii) During extraction of metals, electrolytic refining is used to obtain pure metals. Which material will be used as anode and cathode for the refining of copper metal by this process ? OR (B) (i) Write all the reactions involved in the extraction of Zn from ZnS. (ii) Hydrogen gas is not evolved when most of the metals react with nitric acid. Give reason.

    How the model answer begins

    1. (i) (a) A carbonate ore is changed into its metal oxide by calcination. For example: ZnCO3(s) → (Heat) → ZnO(s) + CO2(g)

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16. Q16Short answer3 marksAsked: 2025

    Design an activity to show that metals are good conductors of heat and have high melting points.

17. Q17Short answer3 marksAsked: 2025

    Samples of four metals A, B, C and D were added one by one to the following solutions. The results obtained were tabulated as follows : | Metal \ Solution | Iron Sulphate | Copper Sulphate | Zinc Sulphate | Aluminium Sulphate | | --- | --- | --- | --- | --- | | A | - | Displacement | No reaction | No reaction | | B | Displacement | Displacement | Displacement | - | | C | Displacement | ? | - | No reaction | | D | No reaction | No reaction | No reaction | No reaction | Use the table above to answer the following questions about metals A, B, C and D : (i) Which is the least reactive metal? (ii) What would be observed if C is added to a solution of copper sulphate? (iii) Arrange the metals A, B, C and D in the order of their decreasing reactivity.

    How the model answer begins

    1. (i) D is the least reactive metal, because it displaces no metal from any of the solutions.

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18. Q18Short answer3 marksAsked: 2025

    Name and describe the most widely used method for refining impure metals ?

    How the model answer begins

    1. The most widely used method for refining impure metals is electrolytic refining. Many metals, such as copper, zinc, tin, nickel, silver and gold, are refined this way.

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19. Q19Long answer3 marksAsked: 2026

    Attempt either (a) or (b) : (a) (i) Write one example each of one metal that is so soft that it can be cut with a knife, and one non-metal that is a good conductor of electricity. (ii) Using the electronic configuration, explain how Mg atom combines with oxygen to form magnesium oxide by transfer of electrons. [Atomic number : Mg = 12, O = 8] OR (b) Give reasons : (i) Metal sulphides and carbonates should be converted to their metal oxides in the process of extraction of metals. (ii) Aluminium oxide is considered as an amphoteric oxide. (iii) Metals like Na, K, Ca and Mg are never found in their free state in nature.

    How the model answer begins

    1. (a) (i) Sodium (Na) is a metal so soft that it can be cut with a knife.

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20. Q20Short answer3 marksAsked: 2026

    Answer the following : (a) Why can the oxides of highly reactive metals not be reduced by carbon ? (b) Why do ionic compounds have high melting and boiling points ? (c) Why is a solder, an alloy of lead and tin, used for welding electrical wires together ?

    How the model answer begins

    1. (a) The oxides of highly reactive metals cannot be reduced by carbon because these metals have more affinity for oxygen than carbon. Sodium, magnesium, calcium and aluminium are examples. So these metals are obtained by…

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21 more questions of this chapter, each with its model answer, in the AskMedha app.

Objective questions with the board’s key (10)

1. 1. CBSE 2026

   17. When an element 'X' reacts with water, it starts floating. Identify the element 'X' :

   • (A) Potassium
   • (B) Calcium ✓
   • (C) Sodium
   • (D) Iron

   Answer: (B)

2. 2. CBSE 2026

   Which of the following is a poor conductor of electricity ?

   • (A) Pb ✓
   • (B) Cu
   • (C) Ag
   • (D) Al

   Answer: (A)

3. 3. CBSE 2026

   The reaction of calcium with cold water is :

   • (A) Less violent, but the heat evolved is sufficient for the hydrogen to catch fire.
   • (B) Very violent and exothermic and hydrogen catches fire.
   • (C) Exothermic, but the heat evolved is not sufficient for the hydrogen to catch fire. ✓
   • (D) Slow and endothermic.

   Answer: (C)

4. 4. CBSE 2026

   When zinc reacts with NaOH, the product formed is :

   • (A) Na2O
   • (B) ZnO
   • (C) Na2ZnO2 ✓
   • (D) Zn(OH)2

   Answer: (C)

5. 5. CBSE 2026

   Which one of the following metals does not react with cold water ?

   • (A) Sodium
   • (B) Potassium
   • (C) Calcium
   • (D) Magnesium ✓

   Answer: (D)

6. 6. CBSE 2026

   Alloys are homogeneous mixture of metal with a metal or non-metal. Which among the following alloys contain non-metal as one of its constituents ?

   • (A) Brass
   • (B) Bronze
   • (C) Amalgam
   • (D) Steel ✓

   Answer: (D)

7. 7. CBSE 2026

   When Mg metal is treated with hot water, it starts floating on the surface of the water. The reason for its different behaviour is :

   • (A) Mg is a lighter element than water.
   • (B) Mg reacts with water to produce H2 gas which helps in floating. ✓
   • (C) Mg reacts with water to produce N2 gas which helps in floating.
   • (D) Mg reacts with water to form CO2 gas which helps in floating.

   Answer: (B)

8. 8. CBSE 2026

   A student observed that his silver jewellery became dull after wearing it for a few months and a grey-black layer was deposited on it. What is the reason for the change in the colour of the silver metal ?

   • (A) The polish on the jewellery wore off after wearing it for a few months.
   • (B) The jewellery got corroded by coming in contact with air, moisture and acids. ✓
   • (C) Dust particles on the jewellery changed its colour.
   • (D) It changed colour due to rusting.

   Answer: (B)

9. 9. CBSE 2026

   19. Which of the following is an amphoteric oxide ?

   • (A) Na2O
   • (B) K2O
   • (C) CO2
   • (D) Al2O3 ✓

   Answer: (D)

10. 10. CBSE 2026

    23. Which gas is liberated when magnesium metal reacts with very dilute HNO3 ?

    • (A) Oxygen
    • (B) Nitrogen
    • (C) Hydrogen ✓
    • (D) Nitrogen dioxide

    Answer: (C)

Questions parents and students ask

How many marks does "Metals and Non-metals" carry in CBSE Class 10 Science?

In the CBSE papers of 2023–2026, this chapter carried about 6 marks and about 3 questions a year; by marks it ranks 7 in Science.

Which are the most important (VVI) questions of "Metals and Non-metals"?

The 20 questions above are from the board’s real papers, each with the years it was asked; the most-asked come first with their full model answers. All 41 written questions of this chapter, with answers, are in the AskMedha app.

Do the answers follow the board’s marking scheme?

Yes. CBSE publishes its marking schemes; every model answer here is written point by point to the marks the board’s own scheme gives, and checked by a second, independent model.