Q 1 – Name some common metals.
Ans. Copper, aluminium, iron, silver, gold, etc
Q 2 – Name some common non-metals.
Ans. Hydrogen, oxygen, carbon, sulphur, phosphorus, etc.
Q 3 – Name the property due to which metals shine.
Ans. Lustre
Q 4 – Give examples of metalloids.
Ans. Antimony, arsenic, silicon, boron, etc.
Q 5 – Name the property due to which metals can be beaten into thin sheets.
Ans. Malleability
Q 6 – Name the metal and non-metal which occur in liquid state.
Ans. Mercury (metal), bromine (non-metal).
Q 7 – State the property of non-metals due to which phosphorus is kept in water.
Ans. Non-metals do not react with water.
Q 8 – Which metal is used for wrapping food items?
Ans. Aluminium
Q 9 – Which metal is less reactive: Copper or zinc?
Ans. Zinc
Q 10 – What is a metal?
Ans. Substances having characteristic properties like malleability, ductility, sonority, conductivity, lustre, – and solidness is called metals. For example, aluminium, copper, zinc, iron, etc.
Q 11 – What are non-metals?
Ans. Substances that are soft and dull, i.e., non-lustrous, non-sonorous, non-ductile, non-malleable and poor conductors of heat and electricity are called non-metals. For example, oxygen, hydrogen, sulphur, etc.
Q 12 – Explain the term ‘malleability’ with suitable examples.
Ans. Malleability is the property of metals due to which they can be beaten into thin sheets. For example, if we beat or hammer any metal like aluminium, zinc, iron, copper, etc., it becomes longer and larger but does not break. Thin sheets can be obtained by this process.
Q 13 – What is ductility? Explain with examples.
Ans. Ductility is one of the properties of metals due to which they can be drawn into wires. For example, aluminium and copper are drawn into wires and used for electrical and different purposes.
Q 14 – Why aluminium is used for wrapping food items?
Ans. Aluminium is a metal and hence possesses malleability property. It can be beaten into thin sheets and can be folded into any shape. It is cheaper than other malleable metals and does not react with food items. That is why it is used as wrapping materials for food items.
Q 15 – How do metals and non-metals react with water?
Ans. Metals produce their hydroxides or oxides and hydrogen when they react with water. Sodium and potassium react with cold water along with the production of a large amount of heat. Magnesium reacts with boiling water and iron with steam. Gold, silver and platinum do not react with water. Non-metals do not react with water.
Q 16 – How do metals and non-metals react with bases?
Ans. How do metals and non-metals react with bases?
Q 17 – How do metals and non-metals react with bases?
Ans. Most of the metals do not react with bases. However, some metals like aluminium, lead and zinc react with strong bases like sodium hydroxide (NaOH) to make complex salts and hydrogen.
Generally, non-metals do not react with bases. Sometimes some complex reactions take place between non-metals and bases.
Q 18 – What is a displacement reaction? Give one example.
Ans. A chemical reaction in which a more reactive metal displaces a less reactive metal is called a displacement, reaction. For example, when zinc (Zn) reacts with copper sulphate (CuSO2), zinc replaces copper being more reactive than copper. The equation is
Q 19 – Distinguish between metals and non-metals on the basis of their physical properties.
or
Compare the physical properties of metals and non-metals.
Ans. Difference between metals and non-metals on the basis of their physical properties.
| Physical Properties | Non-metals | |
| 1. Malleability | Metals are malleable, i.e., they can be beaten into thin sheets. Exception: Mercury | Non-metals are non- malleable. They are broken into pieces when hammered. Hence they are also called brittle. |
| 2. Sonority | Metals are sonorous, i.e., they produce ringing sound when struck. | Non-metals are non-sonorous. |
| 3. Ductility | Metals are ductile, i.e., they can be drawn into wires. Exception: Mercury | Non-metals are non-ductile. |
| 4. Lustre | Metals are lustrous, i.e., they are shiny. | Non-metals are non-lustrous, i.e., they are dull in appearance. Exception: Graphite and iodine. |
| 5. Hardness or solidness | Metals are hard except sodium and potassium. | Non-metals are soft except diamond. |
| 6. Conductivity | Metals are good conductor of heat and electricity. | Non-metals are poor conductor of heat and electricity. Exception: Graphite is a non-conductor of heat and electricity. |
| 7. Density | Metals are of high density except lithium. | Non-metals are of low density. |
| 8. Melting and boiling points. | Metals have high melting and boiling points. | Non-metals have low melting and boiling points except graphite. |
Q 20 – What are the main uses of non-metals?
or
How are non-metals useful to us?
Ans. Like metals, non-metals also play an important role in our lives. They help us in many ways. For example,
(i) We breathe oxygen which is the basis of life of all living things including human beings. Without it, no living beings can exist alive on this earth.
(ii) CO2 which is a non-metal oxide is essential for plants to carry out photosynthesis.
(iii) Non-metals like nitrogen and phosphorus are used in fertilisers for better yield of plant. Phosphorus is used in manufacturing of matchsticks and fireworks
(iv) Non-metal like iodine is used in the purple coloured solution applied on wounds. Sulphur is also used in preparing skin medicines and making ointment due to its fungicidal properties.
(v) Non-metal like chlorine is used in water purification process. Due to its bleaching properties it is used to make bleaching powder.
(vi) Carbon, a non-metal, is used in most of the fuels.
Q 21 – Ram stored copper sulphate solution in a container made of iron. He observed certain changes after a few hours. Can you tell what changes did he observed?
Ans. The blue colour solution of copper sulphate has changed to green colour of ferrous sulphate. The iron container was found to be corroded from many places. A red powdery deposit of copper sulphate was found on the iron container.
Q 22 – Imagine that gold is reactive like copper. Will it be still wanted? Why or why not?
Ans. If gold becomes reactive like copper then its use in ornaments will decline. This is because due to its increase reactivity it will lose its shine frequently which in turn will reduce its demand.
Q 23 – What happens when a copper vessel is exposed to moist air for long? Also write the equation.
Ans. When a copper vessel is exposed to moist air for long, it acquires a dull green coating. This green material is a mixture of copper hydroxide [Cu(OH)2] and copper carbonate (CuC03). The reaction is as follows:
Q 24 – What happens when a magnesium ribbon is heated in presence of air?
Ans. When a magnesium ribbon is heated in presence of air, it burns with a white dazzling flame and a white powdery magnesium oxide is formed.
Q 25 – With the help of equations, explain the reaction of non-metals with oxygen.
Ans. Non-metals react with oxygen to form acidic oxides. But most of the non-metals reacts with oxygen on ignition. The equations follow as:
Q 26 – How do metals and non-metals react with acids?
Ans. Metals react with acids to form respective salts along with the evolution of hydrogen gas that burns with a pop sound. The equation are as follows:
There are some metals like copper, silver, gold and platinum that do not liberate hydrogen with acids. Generally, non-metals do not react with acids.
Q 27 – What are the physical properties of non-metals?
Ans. The physical properties of non-metals are:
- Non-malleable
- Non-sonorous
- Non-lustrous, i.e., dull in appearance
- Non-ductile
- Poor conductor of heat and electricity
Q 28 – Mention the physical properties of metals.
Ans. Physical properties of metals are:
- Malleable
- Lustre
- Sonorous
- Ductile
- Solid
- Good conductor of heat and electricity
Q 29 – What are the differences between metals and non-metals? Explain on the basis of their physical properties.
Ans.
- Metals are malleable and give thin sheets after hammering whereas non-metals are brittle and give no sheets.
- Metals are ductile and can be drawn into wires whereas non-metals are non-ductile and can’t be drawn into wires.
- Metals are sonorous and used in ringing bells whereas non-metals are non-sonorous and cannot be used in ringing bells.
- Metals are good conductors of heat and electricity while non-metals are poor conductors.
Q 30 – Classify the following into metals and non-metals:
Copper, iron, graphite, sulphur, aluminium, oxygen
Ans. Metals: Copper, iron, aluminium
Non-metals: Graphite, sulphur, oxygen
Q 31 – What happens when metals react with water?
Ans. Metals produce their hydroxides or oxides and hydrogen.