CBSE Class 10 Science Chapter-3 Metals and Non-metals Notes & NCERT Solution

Here are some key points from CBSE Class 10 Science Chapter 3 – Metals and Non-metals:

1. Metals:

• Metals are elements that generally have a shiny surface, are good conductors of heat and electricity, and are malleable and ductile.
• Examples of metals include iron, copper, aluminum, gold, and silver.

2. Non-metals:

• Non-metals are elements that are generally poor conductors of heat and electricity and are neither malleable nor ductile.
• Examples of non-metals include oxygen, nitrogen, carbon, sulfur, and phosphorus.

3. Physical Properties of Metals:

• Metals are generally solids at room temperature (except mercury).
• They have high melting and boiling points.
• Metals are good conductors of heat and electricity.
• They are malleable (can be hammered into thin sheets) and ductile (can be drawn into thin wires).
• Metals have a metallic luster.

4. Chemical Properties of Metals:

• Metals react with oxygen to form metal oxides.
• Metals react with water to form metal hydroxides and hydrogen gas.
• Metals react with acids to form salts and hydrogen gas.
• Some metals can displace other metals from their salts in solution.

5. Alloys:

• Alloys are homogeneous mixtures of metals with other elements.
• Common alloys include brass (copper and zinc), bronze (copper and tin), and stainless steel (iron, chromium, and nickel).

6. Uses of Metals:

• Metals have various applications in daily life, including construction, transportation, electrical wiring, and manufacturing.

7. Non-metals:

• Non-metals are generally not malleable or ductile.
• They are poor conductors of heat and electricity.
• Non-metals can gain electrons to form negative ions.

8. Physical Properties of Non-metals:

• Non-metals may exist in different states (solid, liquid, or gas) at room temperature.
• They generally have low melting and boiling points.
• Non-metals are not malleable or ductile.

9. Chemical Properties of Non-metals:

• Non-metals react with oxygen to form non-metal oxides.
• They may react with water to form acidic solutions.
• Non-metals can gain electrons in chemical reactions.

10. Uses of Non-metals:

• Non-metals find applications in various industries, including the production of fertilizers, acids, and polymers.

NCERT Class 10 Science Chapter 3 – “Metals and Non-Metals”:

Physical Properties of Metals and Non-Metals:

Metals:

1. Metals are generally solid at room temperature.
2. They have high melting and boiling points.
3. Metals are good conductors of heat and electricity.
4. They are malleable and ductile.
5. Metals have a metallic luster.

Non-Metals:

1. Non-metals can exist in different states (solid, liquid, or gas).
2. They generally have low melting and boiling points.
3. Non-metals are poor conductors of heat and electricity.
4. They are not malleable or ductile.

Chemical Properties of Metals:

1. Reaction with Oxygen:
   • Metals react with oxygen to form metal oxides.
2. Reaction with Water:
   • Metals react with water to form metal hydroxides and hydrogen gas.
3. Reaction with Acids:
   • Metals react with acids to form salts and release hydrogen gas.
4. Reaction with Solutions of Other Metal Salts:
   • Displacement reactions between metals and the salts of other metals.
5. Reactivity Series:
   • Arrangement of metals based on their reactivity.

Occurrence of Metals:

1. Modes of Occurrence:
   • Ores and minerals.

Extraction of Metals:

1. Enrichment of Ores:
   • Methods to increase the concentration of ores.
2. Extracting Metals Low in the Activity Series:
   • Methods for extracting metals like copper and silver.
3. Extracting Metals in the Middle of the Activity Series:
   • Methods for metals like iron.
4. Extracting Metals Towards the Top of the Activity Series:
   • Methods for metals like potassium and sodium.
5. Refining of Metals:
   • Processes for purifying metals.

Corrosion:

1. Definition and Causes:
   • Introduction to corrosion and factors causing it.
2. Prevention of Corrosion:
   • Methods to prevent or control corrosion.

NCERT Solutions for Class 10 Science Chapter 3 Intext Questions Class 10 Metals and Non Metals NCERT Book Page Number: 40

Question 1: Provide an example of a metal that: (i) exists in a liquid state at room temperature. (ii) can be easily cut with a knife. (iii) is the best conductor of heat. (iv) is a poor conductor of heat. Answer: (i) Mercury (ii) Sodium (iii) Silver (iv) Lead

Question 2: Explain the meanings of malleable and ductile. Answer: Malleable: A metal that can be flattened into thin sheets upon hammering is termed malleable. Ductile: A metal that can be drawn into thin wires is referred to as ductile.

Class 10 Metals and Non Metals NCERT Book Page Number: 46

Question 1: Why is sodium kept immersed in kerosene oil? Answer: Sodium is highly reactive, so it is immersed in kerosene oil to prevent reactions with oxygen, moisture, and carbon dioxide in the air, thus avoiding accidental fires.

Question 2: Write equations for the reactions of (i) iron with steam. (ii) calcium and potassium with water. Answer: (i) 3Fe(s) + 4H2O(g) → Fe3O4(s) + 4H2(g) (ii) 2Ca(s) + 2H2O(l) → 2Ca(OH)2(aq) + H2(g) 2K(s) + 2H2O(l) → 2KOH(aq) + H2(g)

Question 3: Using the given table, answer the following questions about metals A, B, C, and D. (i) Which is the most reactive metal? (ii) What would you observe if B is added to a solution of copper (II) sulfate? (iii) Arrange the metals A, B, C, and D in the order of decreasing reactivity. Answer: (i) Metal B is the most reactive as it displaces iron from its salt solution. (ii) When B is added to copper (II) sulfate solution, a displacement reaction occurs, leading to the formation of a red-brown deposit of copper on metal B. (iii) Decreasing order of reactivity: B > A > C > D

Question 4: Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H2SO4. Answer: Hydrogen gas is produced when dilute hydrochloric acid is added to a reactive metal. Chemical reaction: Fe(s) + H2SO4(aq) → FeSO4(aq) + H2(g)

Question 5: What would you observe when zinc is added to a solution of iron (II) sulfate? Write the chemical reaction that takes place. Answer: Zinc is more reactive than iron. When added to iron (II) sulfate solution, zinc displaces iron, resulting in the formation of colorless zinc sulfate solution and deposition of iron metal on zinc.

Class 10 Metals and Non Metals NCERT Book Page Number: 49

Question 1: (i) Write the electron dot structures for sodium, oxygen, and magnesium. (ii) Show the formation of Na2O and MgO by the transfer of electrons. (iii) What ions are present in these compounds? Answer: (ii) Formation of Na2O and MgO (iii) In Na2O, ions present are Na+ and O2-. In MgO, ions present are Mg2+ and O2-.

Question 2: Why do ionic compounds have high melting points? Answer: Ionic compounds have high melting points due to the strong force of attraction between oppositely charged ions, requiring a significant amount of heat energy to break the attraction.

Class 10 Metals and Non Metals NCERT Book Page Number: 53

Question 1: Define the following terms: (i) Mineral, (ii) Ore, and (iii) Gangue. Answer: (i) Mineral: Naturally occurring materials in which metals or their compounds are found in the earth. (ii) Ore: Minerals from which metals can be extracted conveniently and profitably. (iii) Gangue: Unwanted impurities in an ore, such as sand, rocky material, earth particles, limestone, mica, etc.

Question 2: Name two metals found in nature in the free state. Answer: Gold and platinum

Question 3: What chemical process is used for obtaining a metal from its oxide? Answer: Reduction process is used for obtaining a metal from its oxide, e.g., ZnO(s) + C(s) → Zn(s) + CO(g).

Gold is Metal or Nonmetal? Gold is a metal found in nature in the free state.

Class 10 Metals and Non Metals NCERT Book Page Number: 55

Question 1: Metallic oxides of zinc, magnesium, and copper were heated with the following metals: In which cases will you find displacement reactions taking place? Answer: Displacement reactions will occur in the following cases:

• Zinc oxide with magnesium
• Copper oxide with zinc

Question 2: Which metals do not corrode easily? Answer: Gold and platinum

Question 3: What are alloys? Answer: Alloys are homogeneous mixtures of two or more metals or a metal and a non-metal, such as bronze (copper and tin).

NCERT Solutions for Class 10 Science Chapter 3 Textbook Chapter End Questions

Metals and Nonmetals Class 10 Question 1. Which of the following pairs will give displacement reactions? (a) NaCl solution and copper metal. (b) MgCl2 solution and aluminum metal. (c) FeSO4 solution and silver metal. (d) AgNO3 solution and copper metal. Answer: (d) AgNO3 solution and copper metal.

Question 2. Which 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. Answer: (c) Applying a coating of zinc.

Question 3. An 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 Answer: (a) Calcium.

Question 4. Food cans are coated with tin and not with zinc because (a) zinc is costlier than tin (b) zinc has a higher melting point than tin (c) zinc is less reactive than tin (d) zinc is more reactive than tin. Answer: (d) Zinc is more reactive than tin.

Metals and Nonmetals Class 10 Question 5. You are given a hammer, a battery, a bulb, wires, and a switch. (a) How could you use them to distinguish between samples of metals and non-metals? (b) Assess the usefulness of these tests in distinguishing between metals and non-metals. Answer: (a) Metals can be beaten into thin sheets with a hammer without breaking. Non-metals cannot be beaten with a hammer to form thin sheets. Non-metals break into pieces when hammered. Metals are malleable, while non-metals are not malleable. When metals are connected into a circuit using a battery, bulb, wires, and a switch, current passes through the circuit, and the bulb glows. When non-metals (like sulfur) are connected, the bulb does not light up at all. Metals are good conductors of electricity. (b) Because of malleability, metals can be cast into sheets. Metals are good conductors of electricity, so these can be used for electrical cables.

Question 6. What are amphoteric oxides? Give two examples of amphoteric oxides? OR Write chemical equations that show aluminum oxide reacts with acid as well as a base. [CBSE2011] Answer: Amphoteric oxides are metal oxides that exhibit both acidic and basic behavior. In other words, metal oxides that react with both acids and bases to form salt and water are called amphoteric oxides. Aluminum oxide and zinc oxide are amphoteric in nature.

Question 7. Name two metals that will displace hydrogen from dilute acids and two metals that will not. Answer: (i) Metals above hydrogen in the activity series like sodium and magnesium displace hydrogen from dilute acids. (ii) Metals below hydrogen in the activity series like copper, silver, do not displace hydrogen from dilute acids.

Question 8. In the electrolytic refining of a metal M, what would you take as the anode, the cathode, and the electrolyte? Answer: Cathode – Pure metal Anode – Impure metal Electrolyte – Metal salt solution

Question 9. Pratyush took sulfur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in the figure. (a) What will be the action of the gas on (i) dry litmus paper? (ii) moist litmus paper? (b) Write a balanced chemical equation for the reaction taking place. Answer: (i) Dry litmus paper – no action. (ii) Moist litmus paper – becomes red.

Question 10. State two ways to prevent the rusting of iron. Answer: Ways to prevent rusting of iron are: (a) By painting (b) By galvanizing

Question 11. What type of oxides are formed when non-metals combine with oxygen? Answer: Non-metals combine with oxygen to form acidic oxides or neutral oxides.

Question 12. Give reasons: (a) Platinum, gold, and silver are used to make jewelry. (b) Sodium, potassium, and lithium are stored under oil. (c) Aluminum is a highly reactive metal, yet it is used to make utensils for cooking. (d) Carbonate and sulfide ores are usually converted into oxides during the process of extraction. Answer: (a) Platinum, gold, and silver are used to make jewelry because these are malleable and ductile. These are highly resistant to corrosion. (b) Sodium, potassium, and lithium are very reactive and catch fire when exposed to air. This is due to their low ignition temperature and high reactivity. (c) Aluminum forms a non-reactive layer of aluminum oxide on its surface. This layer prevents aluminum from reacting with other substances. That’s why aluminum is used to make cooking utensils. (d) It is easier to reduce a metal oxide into free metal. Since it is easier to obtain metals from their oxides than from their carbonates or sulfides directly, therefore, the carbonate and sulfide ores are first converted to oxides for extracting the metals.

Question 13. You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels. Answer: The sour substances such as lemon or tamarind juice contain acids. These acids dissolve the coating of copper oxide or basic copper carbonate present on the surface of tarnished copper vessels and make them shining red-brown again.

Question 14. Differentiate between metal and non-metal on the basis of their chemical properties. [CBSE 2017 (Delhi)] Answer: Difference between metals and non-metals

Metals Non-metals (i) Metals form basic oxides or amphoteric oxides. (i) Non-metals form acidic or neutral oxides. (ii) Metals replace hydrogen from acids and form salts. (ii) Non-metals do not replace hydrogen from acids. (iii) With chlorine, metals form chlorides which are electrovalent. (iii) With chlorine, non-metals form chlorides which are covalent. (iv) With hydrogen, few metals form hydrides which are electrovalent. (iv) With hydrogen, non-metals form many stable hydrides which are covalent.

Question 15. A man went door-to-door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. 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 reduced drastically. The lady was upset but after a futile argument, the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he has used? Answer: The dishonest goldsmith dipped the gold bangles in aqua-regia (which contains 1 part of concentrated nitric acid and 3 parts of concentrated hydrochloric acid, by volume). Aqua-regia dissolved a considerable amount of gold from gold bangles and hence reduced their weight drastically. The dishonest goldsmith can recover the dissolved gold from aqua-regia by a suitable treatment.

Question 16. Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron). Answer: (i) Copper is a better conductor of heat than steel. (ii) Copper does not corrode easily. But steel corrodes easily. (iii) Copper does not react with water at any temperature, whereas iron reacts with water on heating.

• CBSE Class 10 Science Chapter-2 Acids, Bases and Salts Notes & NCERT Solution
• CBSE Class 10 Science Chapter-3 Metals and Non-metals Notes & NCERT Solution
• CBSE Class 10 Science Chapter-1 Chemical Reactions and Equations Notes & NCERT Solution
• CBSE Class 10 Science Chapter-4 Carbon and its Compounds Notes & NCERT Solution