Key Points

Malleability is the property that allows materials to be beaten into thin sheets. Metals like gold, silver, and aluminium are highly malleable, while non-metals are brittle and break when hammered.

Ductility is the property that allows materials to be drawn into thin wires. Metals such as copper and aluminium are ductile and used for electrical wiring, whereas non-metals are not ductile.

Metals typically have a shiny appearance known as metallic lustre and are generally hard. In contrast, non-metals are usually dull in appearance and are not as hard as metals.

Metals are sonorous, meaning they produce a ringing sound when struck. Non-metals, like wood or coal, produce a dull sound and are not sonorous.

Metals are good conductors of heat, which is why they are used to make cooking vessels. Non-metals like wood and plastic are poor conductors of heat and are used for handles.

Metals are good conductors of electricity, allowing electric current to pass through them easily. Non-metals are poor conductors of electricity, also known as insulators.

Metals react with oxygen to form metal oxides, which are generally basic in nature. For example, magnesium oxide dissolved in water turns red litmus paper blue.

Non-metals react with oxygen to form non-metal oxides, which are acidic in nature. For example, sulfur dioxide ($SO_2$) dissolved in water forms sulfurous acid ($H_2SO_3$), which turns blue litmus paper red.

Rusting is the process where iron objects develop a brown, flaky deposit called rust when exposed to both air and water. This gradual deterioration of a metal is called corrosion.

Rusting of iron can be prevented by protecting it from moist air. Common methods include painting, oiling, greasing, and galvanisation, which is coating the iron with a layer of zinc.

Not all metals are hard solids; sodium and potassium are soft enough to be cut with a knife. Mercury is a metal that is liquid at room temperature.

Some elements are highly reactive. Sodium is a metal stored in kerosene to prevent its vigorous reaction with air and water, while phosphorus, a non-metal, is stored in water to prevent it from catching fire in air.

Non-metals are vital for life. Oxygen ($\text{O}_2$) is essential for breathing, nitrogen ($\text{N}_2$) is used in fertilisers for plant growth, and carbon (C) is the fundamental building block of all living organisms.

Metals and non-metals are sub-categories of elements. An element is a fundamental substance that cannot be broken down into simpler substances by chemical means.