Class 8 Science – Chapter 4: Materials: Metals and Non-Metals

1. Introduction

Everything around us is made of materials. These materials can be classified into metals and non-metals based on their physical and chemical properties.

For example:

Metals

Iron
Copper
Aluminium
Gold
Silver

Non-Metals

Oxygen
Carbon
Sulphur
Phosphorus
Nitrogen

Metals are usually hard, shiny, and good conductors of heat and electricity, while non-metals generally have opposite properties.

2. Physical Properties of Metals

Metals have several common physical properties.

1. Lustre (Shiny Surface)

Metals have a shiny appearance.

Example:

Gold jewellery
Silver utensils

This shining property is called lustre.

2. Hardness

Most metals are hard and strong.

Example:

Iron is very hard and used to make machines and tools.

However, some metals like sodium and potassium are soft.

3. Malleability

Metals can be hammered into thin sheets.

Example:

Aluminium foil used for wrapping food
Gold sheets used in decoration

This property is called malleability.

4. Ductility

Metals can be drawn into thin wires.

Example:

Copper wires used in electrical wiring.

This property is called ductility.

5. Conductivity

Metals are good conductors of heat and electricity.

Examples:

Copper wires conduct electricity.
Aluminium utensils conduct heat.

6. Sonorous Nature

Metals produce a ringing sound when struck.

Example:

Bells are made from metals.

This property is called sonority.

3. Physical Properties of Non-Metals

Non-metals generally show properties opposite to metals.

1. Dull Appearance

Non-metals usually do not shine.

Example:

Coal
Sulphur

2. Brittle Nature

Non-metals break easily when hammered.

Example:

Coal breaks into pieces.

3. Poor Conductors

Most non-metals are poor conductors of heat and electricity.

Example:

Sulphur does not conduct electricity.

4. Non-Sonorous

Non-metals do not produce sound when struck.

4. Chemical Properties of Metals

1. Reaction with Oxygen

Metals react with oxygen to form metal oxides.

Example:

Magnesium + Oxygen → Magnesium oxide

Magnesium burns with a bright white flame.

2. Reaction with Water

Some metals react with water to form metal hydroxide and hydrogen gas.

Example:

Sodium + Water → Sodium hydroxide + Hydrogen

This reaction can be very violent.

3. Reaction with Acids

Metals react with acids to produce salt and hydrogen gas.

Example:

Zinc + Hydrochloric acid → Zinc chloride + Hydrogen

Hydrogen gas can be identified by the pop sound test.

5. Chemical Properties of Non-Metals

1. Reaction with Oxygen

Non-metals react with oxygen to form non-metal oxides.

Example:

Carbon + Oxygen → Carbon dioxide

2. Reaction with Water

Most non-metals do not react with water.

3. Reaction with Acids

Non-metals generally do not react with acids.

6. Uses of Metals

Metals are used in many important things.

Iron

Construction of buildings
Making machines

Copper

Electrical wires

Aluminium

Cooking utensils
Aircraft bodies

Gold and Silver

Jewellery

7. Uses of Non-Metals

Non-metals also have many uses.

Oxygen

Breathing
Medical use

Nitrogen

Fertilizers

Carbon

Fuel

Chlorine

Water purification

8. Difference Between Metals and Non-Metals

Property	Metals	Non-Metals
Appearance	Shiny	Dull
Hardness	Hard	Usually soft
Malleability	Can be hammered into sheets	Not malleable
Ductility	Can form wires	Not ductile
Conductivity	Good conductors	Poor conductors
Sound	Sonorous	Non-sonorous

9. Displacement Reaction

A more reactive metal can displace a less reactive metal from its compound.

Example:

Iron + Copper sulphate → Iron sulphate + Copper

Iron replaces copper because it is more reactive.

10. Corrosion of Metals

When metals react with air and moisture, they form rust or other compounds.

Example:

Iron + Oxygen + Water → Rust

This process is called corrosion.

11. Prevention of Corrosion

Corrosion can be prevented by:

Painting
Oiling or greasing
Galvanization (coating with zinc)

Example: Iron gates are painted to prevent rust.

12. Conclusion

Metals and non-metals are important materials in our daily life. Metals are strong, shiny, malleable, ductile, and good conductors of heat and electricity, which makes them useful for construction, electrical wiring, and tools. Non-metals have different properties and are useful in fertilizers, medicines, fuels, and water purification.

Understanding the properties and uses of metals and non-metals helps us choose the right materials for different purposes and understand many chemical reactions in everyday life.

Class 8 Science – Chapter 4

Materials: Metals and Non-Metals (Detailed Explanation)

1. Introduction

All the objects around us are made from different materials. These materials are obtained from the earth’s crust and are mainly classified into two groups:

Metals
Non-metals

Examples of metals include iron, copper, aluminium, silver, and gold, while examples of non-metals include oxygen, carbon, sulphur, nitrogen, and phosphorus.

Metals and non-metals have different physical and chemical properties, which determine their uses in daily life.

2. Physical Properties of Metals

Physical properties are the characteristics that can be observed without changing the chemical composition of the substance.

1. Lustre (Shiny Surface)

Metals have a shiny appearance. This shining property is called lustre.

Examples:

Gold jewellery shines.
Silver utensils look bright.
Copper wires are shiny.

Because of this property, metals are often used in ornaments and decorative items.

2. Hardness

Most metals are hard and strong. They cannot be easily cut or broken.

Examples:

Iron is used to make machines and tools because it is strong.
Steel is used in building construction.

However, some metals such as sodium and potassium are soft and can be cut with a knife.

3. Malleability

Metals can be hammered into thin sheets without breaking.

This property is called malleability.

Examples:

Aluminium sheets are used for packaging food.
Gold and silver sheets are used in decoration and jewellery.

Gold is the most malleable metal.

4. Ductility

Metals can be drawn into thin wires.

This property is called ductility.

Examples:

Copper wires are used in electrical wiring.
Aluminium wires are used in power cables.

Gold is also the most ductile metal.

5. Conductivity

Metals are good conductors of heat and electricity.

Examples:

Electrical Conductivity

Copper wires carry electricity in homes.
Aluminium is used in power transmission lines.

Heat Conductivity

Aluminium utensils are used for cooking.
Iron pans conduct heat easily.

6. Sonorous Nature

Metals produce a ringing sound when struck with another object.

This property is called sonority.

Examples:

School bells
Musical instruments

Because of this property, bells are usually made of metal.

3. Physical Properties of Non-Metals

Non-metals generally show properties opposite to metals.

1. Dull Appearance

Most non-metals do not shine and appear dull.

Examples:

Coal
Sulphur

However, iodine is an exception because it has some shine.

2. Brittle Nature

Non-metals are brittle, meaning they break easily when hammered.

Example:

Coal breaks into pieces.

They cannot be converted into sheets or wires.

3. Poor Conductors

Non-metals are generally poor conductors of heat and electricity.

Example:

Sulphur does not conduct electricity.

However, graphite (a form of carbon) is an exception because it can conduct electricity.

4. Non-Sonorous

Non-metals do not produce sound when struck.

Example:

Coal or sulphur will not make a ringing sound when hit.

4. Chemical Properties of Metals

Chemical properties describe how a substance reacts with other substances.

1. Reaction with Oxygen

Metals react with oxygen to form metal oxides.

Example:

Magnesium + Oxygen → Magnesium oxide

Magnesium burns with a bright white flame.

Metal oxides are usually basic in nature.

2. Reaction with Water

Some metals react with water to form metal hydroxide and hydrogen gas.

Example:

Sodium + Water → Sodium hydroxide + Hydrogen gas

This reaction is very fast and sometimes dangerous.

Different metals react with water at different speeds.

3. Reaction with Acids

Metals react with acids to produce salt and hydrogen gas.

Example:

Zinc + Hydrochloric acid → Zinc chloride + Hydrogen gas

Hydrogen gas can be identified by the pop sound test.

5. Chemical Properties of Non-Metals

1. Reaction with Oxygen

Non-metals react with oxygen to form non-metal oxides.

Example:

Carbon + Oxygen → Carbon dioxide

Non-metal oxides are usually acidic in nature.

2. Reaction with Water

Most non-metals do not react with water.

Example:

Sulphur does not react with water.

3. Reaction with Acids

Non-metals generally do not react with acids.

6. Uses of Metals

Metals are widely used because they are strong and good conductors.

Iron

Building construction
Machines
Tools

Copper

Electrical wires
Electric motors

Aluminium

Cooking utensils
Aircraft bodies
Foil for food packaging

Gold and Silver

Jewellery
Decorative items

7. Uses of Non-Metals

Non-metals are also very important.

Oxygen

Breathing
Medical use in hospitals

Nitrogen

Making fertilizers
Preserving food

Carbon

Fuel (coal)
Pencil lead (graphite)

Chlorine

Purifying drinking water
Making disinfectants

8. Displacement Reactions

A more reactive metal can replace a less reactive metal from its compound.

Example:

Iron + Copper sulphate → Iron sulphate + Copper

Here iron displaces copper from copper sulphate solution.

This reaction is called a displacement reaction.

9. Corrosion

When metals react with air and moisture, they slowly get damaged.

Example:

Iron + Oxygen + Water → Rust

This process is called corrosion.

Rust is a reddish-brown substance formed on iron.

10. Prevention of Corrosion

Corrosion can be prevented by several methods.

1. Painting

Painting creates a protective layer on the metal surface.

Example: Iron gates are painted.

2. Oiling or Greasing

Oil prevents contact with air and water.

Example: Machine parts.

3. Galvanization

Iron is coated with a layer of zinc.

Example: Water pipes.

11. Reactivity of Metals

Different metals react at different speeds.

Highly reactive metals:

Sodium
Potassium

Moderately reactive metals:

Iron
Zinc

Less reactive metals:

Gold
Silver

12. Conclusion

Metals and non-metals are very important materials in science and daily life. Metals are strong, shiny, malleable, ductile, and good conductors of heat and electricity, which makes them useful for tools, machines, construction, and electrical wiring.

Non-metals have different properties and are used in fertilizers, fuels, medicines, and water purification.

Understanding metals and non-metals helps us learn about chemical reactions, materials used in industries, and many processes that occur in everyday life.

Here are 80 MCQs from Class 8 Science – Chapter 4: Materials: Metals and Non-Metals.
Each question has four options and the correct answer.

80 MCQs – Metals and Non-Metals (Class 8 Science)

1–20 Basic MCQs

Which of the following is a metal?
A. Sulphur
B. Iron
C. Oxygen
D. Carbon
Answer: B
Which of the following is a non-metal?
A. Copper
B. Aluminium
C. Sulphur
D. Iron
Answer: C
Metals are generally
A. Dull
B. Shiny
C. Soft
D. Powdery
Answer: B
The shining property of metals is called
A. Hardness
B. Lustre
C. Ductility
D. Sonority
Answer: B
The property by which metals can be beaten into sheets is called
A. Ductility
B. Malleability
C. Conductivity
D. Hardness
Answer: B
The property of drawing metals into wires is called
A. Ductility
B. Malleability
C. Sonority
D. Brittleness
Answer: A
Metals are good conductors of
A. Heat and electricity
B. Water
C. Air
D. Light
Answer: A
Which metal is used for electrical wiring?
A. Copper
B. Sulphur
C. Phosphorus
D. Nitrogen
Answer: A
Non-metals are generally
A. Hard
B. Shiny
C. Brittle
D. Sonorous
Answer: C
Which of the following is a non-metal?
A. Carbon
B. Zinc
C. Copper
D. Aluminium
Answer: A
Metals produce sound when struck. This property is called
A. Sonority
B. Malleability
C. Conductivity
D. Hardness
Answer: A
Which metal is used to make utensils?
A. Aluminium
B. Carbon
C. Sulphur
D. Phosphorus
Answer: A
Which of the following metals is liquid at room temperature?
A. Iron
B. Mercury
C. Copper
D. Zinc
Answer: B
Non-metals are generally
A. Good conductors
B. Poor conductors
C. Magnetic
D. Heavy
Answer: B
Coal is an example of
A. Metal
B. Non-metal
C. Alloy
D. Gas
Answer: B
Graphite is a form of
A. Iron
B. Carbon
C. Copper
D. Aluminium
Answer: B
Graphite is used in
A. Jewellery
B. Pencil lead
C. Building construction
D. Cooking utensils
Answer: B
Which property allows metals to be made into wires?
A. Hardness
B. Ductility
C. Sonority
D. Brittleness
Answer: B
Metals are generally
A. Dull
B. Brittle
C. Hard
D. Gaseous
Answer: C
Which of the following is not a metal?
A. Iron
B. Copper
C. Aluminium
D. Oxygen
Answer: D

21–40 Intermediate MCQs

Metals react with oxygen to form
A. Metal oxides
B. Non-metal oxides
C. Water
D. Salt
Answer: A
Magnesium burns in air to form
A. Magnesium oxide
B. Magnesium chloride
C. Magnesium sulphate
D. Magnesium nitrate
Answer: A
Non-metals react with oxygen to form
A. Basic oxides
B. Acidic oxides
C. Neutral oxides
D. Salts
Answer: B
Rust is mainly
A. Iron oxide
B. Copper oxide
C. Zinc oxide
D. Aluminium oxide
Answer: A
Rusting requires
A. Air only
B. Water only
C. Air and moisture
D. Heat only
Answer: C
The reddish-brown coating on iron is called
A. Rust
B. Salt
C. Oxide
D. Acid
Answer: A
Which gas is released when metals react with acids?
A. Oxygen
B. Hydrogen
C. Nitrogen
D. Carbon dioxide
Answer: B
The gas released in metal-acid reaction gives a
A. Pop sound
B. Whistle sound
C. Loud explosion
D. Crack sound
Answer: A
Zinc reacts with hydrochloric acid to produce
A. Zinc chloride and hydrogen
B. Zinc oxide
C. Zinc sulphate
D. Zinc nitrate
Answer: A
Metals that react strongly with water are
A. Sodium and potassium
B. Copper and silver
C. Gold and platinum
D. Zinc and iron
Answer: A
Which metal reacts violently with water?
A. Sodium
B. Copper
C. Gold
D. Silver
Answer: A
Displacement reaction occurs when
A. Less reactive metal replaces more reactive metal
B. More reactive metal replaces less reactive metal
C. Two metals mix
D. Gas forms
Answer: B
Iron + Copper sulphate →
A. Iron sulphate + Copper
B. Copper sulphate
C. Iron oxide
D. Copper oxide
Answer: A
Copper cannot displace
A. Iron
B. Silver
C. Gold
D. Zinc
Answer: A
Metals generally form
A. Positive ions
B. Negative ions
C. Neutral ions
D. No ions
Answer: A
Non-metals generally form
A. Positive ions
B. Negative ions
C. Neutral ions
D. Metallic ions
Answer: B
Oxygen is
A. Metal
B. Non-metal
C. Alloy
D. Mineral
Answer: B
Chlorine is used for
A. Water purification
B. Cooking
C. Jewellery
D. Painting
Answer: A
Nitrogen is used in making
A. Fertilizers
B. Iron
C. Plastic
D. Glass
Answer: A
Carbon dioxide is produced when
A. Carbon burns in oxygen
B. Hydrogen burns
C. Nitrogen reacts
D. Oxygen reacts with water
Answer: A

41–60 Higher Level MCQs

Which metal is used in aircraft bodies?
A. Aluminium
B. Copper
C. Zinc
D. Iron
Answer: A
Which metal is used for jewellery?
A. Gold
B. Sodium
C. Iron
D. Zinc
Answer: A
The process of coating iron with zinc is called
A. Galvanization
B. Rusting
C. Corrosion
D. Painting
Answer: A
Which method prevents rusting?
A. Painting
B. Oiling
C. Galvanization
D. All of these
Answer: D
Metals are generally
A. Soft
B. Hard
C. Gaseous
D. Liquid
Answer: B
Which metal is most malleable?
A. Gold
B. Iron
C. Copper
D. Aluminium
Answer: A
Which metal is most ductile?
A. Gold
B. Zinc
C. Iron
D. Lead
Answer: A
The hardest natural metal is
A. Iron
B. Gold
C. Silver
D. Copper
Answer: A
Which metal is used in electric cables?
A. Copper
B. Sulphur
C. Carbon
D. Oxygen
Answer: A
Non-metals are generally
A. Sonorous
B. Non-sonorous
C. Magnetic
D. Elastic
Answer: B
Coal is mainly made of
A. Carbon
B. Iron
C. Copper
D. Aluminium
Answer: A
Which non-metal is essential for breathing?
A. Oxygen
B. Nitrogen
C. Hydrogen
D. Carbon
Answer: A
Nitrogen makes up about
A. 78% of air
B. 50% of air
C. 30% of air
D. 10% of air
Answer: A
Which element is used in matchsticks?
A. Phosphorus
B. Iron
C. Zinc
D. Copper
Answer: A
Diamond is a form of
A. Carbon
B. Iron
C. Oxygen
D. Nitrogen
Answer: A
Diamond is the
A. Softest substance
B. Hardest natural substance
C. Lightest metal
D. Best conductor
Answer: B
Graphite is used as
A. Lubricant
B. Fuel
C. Medicine
D. Fertilizer
Answer: A
The chemical symbol of iron is
A. Fe
B. Ir
C. In
D. I
Answer: A
The chemical symbol of copper is
A. Cu
B. Co
C. Cp
D. Cr
Answer: A
The chemical symbol of aluminium is
A. Al
B. Au
C. Ag
D. Ar
Answer: A

61–80 Advanced MCQs

Which metal does not react easily with air?
A. Gold
B. Sodium
C. Potassium
D. Calcium
Answer: A
Rusting is a type of
A. Corrosion
B. Combustion
C. Evaporation
D. Freezing
Answer: A
Which metal is stored in kerosene?
A. Sodium
B. Copper
C. Iron
D. Aluminium
Answer: A
Metals react with acids to produce
A. Hydrogen gas
B. Oxygen gas
C. Nitrogen gas
D. Carbon dioxide
Answer: A
Which is the best conductor of electricity?
A. Copper
B. Iron
C. Aluminium
D. Silver
Answer: D
Which non-metal is used in fertilizers?
A. Nitrogen
B. Carbon
C. Sulphur
D. Oxygen
Answer: A
Which metal is used for coins?
A. Copper
B. Sulphur
C. Carbon
D. Oxygen
Answer: A
Which non-metal is used for water purification?
A. Chlorine
B. Nitrogen
C. Carbon
D. Sulphur
Answer: A
The most reactive metal is
A. Potassium
B. Copper
C. Gold
D. Silver
Answer: A
Which metal does not rust?
A. Aluminium
B. Iron
C. Copper
D. Zinc
Answer: A
Stainless steel contains
A. Iron
B. Chromium
C. Nickel
D. All of these
Answer: D
Which metal is used in food wrapping foil?
A. Aluminium
B. Iron
C. Copper
D. Zinc
Answer: A
Which metal is used in batteries?
A. Zinc
B. Iron
C. Gold
D. Copper
Answer: A
The green coating on copper is
A. Copper carbonate
B. Copper sulphate
C. Copper oxide
D. Copper nitrate
Answer: A
Which metal is used for water pipes?
A. Iron
B. Copper
C. PVC
D. Aluminium
Answer: B
Which metal is used for railway tracks?
A. Steel
B. Copper
C. Aluminium
D. Gold
Answer: A
Which metal is used for coins and utensils?
A. Copper
B. Sulphur
C. Carbon
D. Nitrogen
Answer: A
Which non-metal is used in crackers?
A. Sulphur
B. Iron
C. Copper
D. Zinc
Answer: A
Which non-metal is used in medicines and disinfectants?
A. Chlorine
B. Oxygen
C. Carbon
D. Nitrogen
Answer: A
The hardest natural substance is
A. Diamond
B. Gold
C. Iron
D. Silver
Answer: A

If you want, I can also create very important exam material for this chapter, such as:

Here are 10 Case Study Questions from Class 8 Science – Chapter 4: Materials: Metals and Non-Metals (CBSE exam pattern).

Case Study Questions

Chapter: Metals and Non-Metals

Case Study 1 – Properties of Metals

Rohit observed that metals like iron, copper, and aluminium are shiny, strong, and can conduct electricity. He also noticed that copper wires are used in electrical circuits because they allow electricity to pass through easily.

Questions

What property of metals allows them to conduct electricity?
Answer: Conductivity.
Which metal is commonly used in electrical wires?
A. Copper
B. Sulphur
C. Carbon
D. Nitrogen

Answer: A

Name one property of metals.
Answer: Metals are shiny (lustrous).

Case Study 2 – Non-Metals

Priya noticed that coal and sulphur are dull in appearance and break easily when hammered. Her teacher explained that these materials are examples of non-metals.

Questions

Which property of non-metals causes them to break easily?
Answer: Brittleness.
Coal is an example of
A. Metal
B. Non-metal
C. Alloy
D. Gas

Answer: B

Write one property of non-metals.
Answer: Non-metals are poor conductors of electricity.

Case Study 3 – Malleability

A goldsmith was hammering a piece of gold into very thin sheets to make jewellery. This shows a special property of metals.

Questions

What is the property of metals shown in this example?
Answer: Malleability.
Which metal is the most malleable?
A. Gold
B. Iron
C. Copper
D. Aluminium

Answer: A

Write one use of malleable metals.
Answer: Making jewellery and metal sheets.

Case Study 4 – Ductility

Electric wires used in homes are made of copper. Copper can be stretched into thin wires without breaking.

Questions

Which property allows metals to be drawn into wires?
Answer: Ductility.
Which metal is commonly used for electric wires?
A. Sulphur
B. Copper
C. Carbon
D. Phosphorus

Answer: B

Write one more example of a ductile metal.
Answer: Aluminium.

Case Study 5 – Reaction with Oxygen

When magnesium ribbon is burned in air, it burns with a bright white flame and forms magnesium oxide.

Questions

Magnesium reacts with which gas in air?
Answer: Oxygen.
Magnesium oxide is an example of
A. Metal oxide
B. Non-metal oxide
C. Acid
D. Salt

Answer: A

Write the chemical reaction for this process.
Answer:
Magnesium + Oxygen → Magnesium oxide

Case Study 6 – Reaction with Acids

A student added zinc granules to dilute hydrochloric acid. Bubbles of gas were produced and the gas produced a pop sound when tested.

Questions

Which gas is produced in this reaction?
Answer: Hydrogen gas.
What test confirms the presence of hydrogen gas?
Answer: Pop sound test.
What is formed when zinc reacts with hydrochloric acid?
Answer: Zinc chloride.

Case Study 7 – Rusting of Iron

An iron gate left in the open air for many months developed a reddish-brown coating called rust.

Questions

What is rusting?
Answer: Rusting is the corrosion of iron caused by reaction with oxygen and moisture.
What is rust mainly made of?
Answer: Iron oxide.
Name one method to prevent rusting.
Answer: Painting.

Case Study 8 – Displacement Reaction

When an iron nail is dipped in copper sulphate solution, the blue solution gradually turns green and copper metal is deposited on the nail.

Questions

What type of reaction is this?
Answer: Displacement reaction.
Which metal is more reactive in this reaction?
Answer: Iron.
What compound is formed in the solution?
Answer: Iron sulphate.

Case Study 9 – Uses of Non-Metals

Non-metals are very important in daily life. Oxygen is necessary for breathing, nitrogen is used in fertilizers, and chlorine is used to purify drinking water.

Questions

Which non-metal is essential for breathing?
Answer: Oxygen.
Nitrogen is mainly used in
A. Fertilizers
B. Jewellery
C. Tools
D. Machinery

Answer: A

Which non-metal is used for water purification?
Answer: Chlorine.

Case Study 10 – Prevention of Corrosion

Corrosion damages metals over time. Iron objects are often painted or coated with zinc to protect them from rust.

Questions

What is the process of coating iron with zinc called?
Answer: Galvanization.
Which metal is commonly coated with zinc to prevent rusting?
Answer: Iron.
Name one other method to prevent corrosion.
Answer: Oiling or greasing.

Here are 20 Short Answer Questions and 10 Long Answer Questions from Class 8 Science – Chapter 4: Materials: Metals and Non-Metals.

Short Answer Questions (20)

1. What are metals?

Answer: Metals are substances that are generally hard, shiny, malleable, ductile, and good conductors of heat and electricity.

2. What are non-metals?

Answer: Non-metals are substances that are generally dull, brittle, and poor conductors of heat and electricity.

3. What is lustre?

Answer: The shiny appearance of metals is called lustre.

4. What is malleability?

Answer: The property by which metals can be hammered into thin sheets is called malleability.

5. What is ductility?

Answer: The property by which metals can be drawn into thin wires is called ductility.

6. What does sonorous mean?

Answer: Sonorous means producing a ringing sound when struck.

7. Name two metals.

Answer: Iron and copper.

8. Name two non-metals.

Answer: Carbon and sulphur.

9. Which metal is used for electrical wires?

Answer: Copper.

10. Which metal is used in cooking utensils?

Answer: Aluminium.

11. Why are metals used for making cooking utensils?

Answer: Because metals are good conductors of heat.

12. What happens when metals react with oxygen?

Answer: Metals react with oxygen to form metal oxides.

13. What happens when non-metals react with oxygen?

Answer: Non-metals react with oxygen to form non-metal oxides.

14. What is rust?

Answer: Rust is a reddish-brown substance formed when iron reacts with oxygen and moisture.

15. What is corrosion?

Answer: Corrosion is the slow damage of metals caused by reaction with air and moisture.

16. What is galvanization?

Answer: Galvanization is the process of coating iron with zinc to prevent rusting.

17. What is a displacement reaction?

Answer: A reaction in which a more reactive metal replaces a less reactive metal from its compound.

18. Name one metal that reacts with water.

Answer: Sodium.

19. Why are non-metals poor conductors of electricity?

Answer: Because they do not have free electrons to carry electric current.

20. Give one use of chlorine.

Answer: Chlorine is used to purify drinking water.

Long Answer Questions (10)

1. Write the physical properties of metals.

Answer:
Metals have several physical properties:

They are shiny (lustrous).
They are hard and strong.
They are malleable (can be hammered into sheets).
They are ductile (can be drawn into wires).
They are good conductors of heat and electricity.
They are sonorous (produce sound when struck).

2. Write the physical properties of non-metals.

Answer:
Non-metals generally show opposite properties to metals:

They are dull in appearance.
They are brittle and break easily.
They are poor conductors of heat and electricity.
They are non-sonorous.
They cannot be converted into sheets or wires.

3. Explain the chemical properties of metals.

Answer:
Metals show the following chemical properties:

Metals react with oxygen to form metal oxides.
Metals react with water to produce metal hydroxide and hydrogen gas.
Metals react with acids to produce salt and hydrogen gas.

4. Explain the chemical properties of non-metals.

Answer:

Non-metals react with oxygen to form non-metal oxides.
Most non-metals do not react with water.
Non-metals usually do not react with acids.

5. Explain displacement reactions with an example.

Answer:
A displacement reaction occurs when a more reactive metal replaces a less reactive metal from its compound.

Example:
Iron + Copper sulphate → Iron sulphate + Copper

Here iron displaces copper from copper sulphate.

6. Explain rusting and its prevention.

Answer:
Rusting is the corrosion of iron caused by reaction with oxygen and moisture. It forms a reddish-brown substance called rust.

Methods to prevent rusting:

Painting
Oiling or greasing
Galvanization
Alloy formation

7. Write the uses of metals.

Answer:

Metals are used for many purposes:

Iron for building construction.
Copper for electrical wires.
Aluminium for utensils and aircraft bodies.
Gold and silver for jewellery.

8. Write the uses of non-metals.

Answer:

Non-metals are used in many ways:

Oxygen for breathing.
Nitrogen for fertilizers.
Carbon as fuel.
Chlorine for water purification.

9. Differentiate between metals and non-metals.

Metals	Non-Metals
Shiny	Dull
Hard	Brittle
Good conductors	Poor conductors
Malleable	Not malleable
Ductile	Not ductile

10. Explain why metals are useful in daily life.

Answer:
Metals are very useful because they are strong, durable, and good conductors of heat and electricity. They are used in construction, transportation, electrical wiring, cooking utensils, and machinery.

Here is an 80 Marks Test Paper for Class 8 Science – Chapter 4: Materials: Metals and Non-Metals.

Class 8 Science Test

Chapter 4: Materials – Metals and Non-Metals

Time: 2 Hours
Maximum Marks: 80

Section A – MCQ (1 × 20 = 20 Marks)

Choose the correct answer.

Which of the following is a metal?
a) Sulphur
b) Iron
c) Carbon
d) Phosphorus
Which metal is liquid at room temperature?
a) Iron
b) Mercury
c) Copper
d) Zinc
Metals are generally:
a) Dull
b) Brittle
c) Lustrous
d) Soft
Which of the following is a non-metal?
a) Aluminium
b) Copper
c) Oxygen
d) Iron
Metals are good conductors of:
a) Heat and electricity
b) Water
c) Air
d) Light
Which property allows metals to be drawn into wires?
a) Malleability
b) Ductility
c) Hardness
d) Sonority
Which property allows metals to be beaten into sheets?
a) Ductility
b) Malleability
c) Conductivity
d) Hardness
Which metal is used in electrical wires?
a) Copper
b) Gold
c) Iron
d) Aluminium
Non-metals are generally:
a) Hard
b) Dull
c) Shiny
d) Malleable
Which of the following is brittle?
a) Iron
b) Aluminium
c) Sulphur
d) Copper
Metals react with oxygen to form:
a) Metal oxides
b) Acids
c) Bases
d) Salts
Non-metals react with oxygen to form:
a) Basic oxides
b) Acidic oxides
c) Neutral oxides
d) Salts
Which gas is produced when metals react with acids?
a) Oxygen
b) Hydrogen
c) Nitrogen
d) Carbon dioxide
Which metal reacts with water to form hydrogen gas?
a) Sodium
b) Copper
c) Silver
d) Gold
Rust is formed on:
a) Copper
b) Iron
c) Aluminium
d) Gold
Rusting occurs in presence of:
a) Oxygen and water
b) Water only
c) Oxygen only
d) Carbon dioxide
Which of the following is used in fertilizers?
a) Nitrogen
b) Iron
c) Aluminium
d) Copper
Which non-metal is essential for breathing?
a) Nitrogen
b) Oxygen
c) Sulphur
d) Chlorine
Which metal is used in making jewellery?
a) Gold
b) Sodium
c) Calcium
d) Magnesium
Which non-metal is used in water purification?
a) Chlorine
b) Carbon
c) Nitrogen
d) Sulphur