ICSE Class 7 Answered

Lustre

All metals in their pure state have a shine and can be polished to give a highly reflective surface.

Malleability

Metals have the ability to withstand high tensile strength and can be made into thin sheets. This property of metals is called malleability.

Ductility

 Metals can also be drawn into thin wires. The ability of metals to be drawn into wires is called ductility.

Example: Gold and silver are the most ductile metals.

Conduction of Heat

Metals are good conductors of heat and have high melting points.

Example: Silver and copper are very good conductors of electricity.

Exceptions: Lead and mercury are poor conductors of heat.

Conduction of Electricity

 Metals are good conductors of electricity.

 Sonorous

 Metals which produce a sound on striking a hard surface are said to be sonorous.

2. Metal oxides are basic in nature:

When we add water to metallic oxide, it will form hydroxide which turns red litmus blue.

That means it is basic in nature.

Example:

Magnesium oxide, when dissolved in water, forms magnesium hydroxide which is basic in nature.

MgO + H₂O → Mg(OH)₂

3. Factors affecting rate of corrosion:

• Temperature
• Oxygen
• Humidity