Properties and uses of metals

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Metals are amongst our most valuable resources. Thousands of years ago, people used metals such as Copper and Iron to make weapons and everyday objects. These metals are still in use today.

[edit] Properties of metals

The five most used metals are:

The general physical properties of metals are:

They are strong and hard.
They are solids at room temperature (except for Mercury, which is the only metal to be liquid at room temperature)
They have a shiny luster when polished.
They make good heat conductors and electrical conductors.
They are dense
They produce a sonorous sound when struck.

The properties of metals make them suitable for different uses in daily life.

Copper is a good conductor of electricity and is ductile. Therefore Copper is used for electrical cables.
Gold and Silver are very malleable, ductile and very unreactive. Gold and silver are used to make intricate jewellery which does not tarnish. Gold can also be used for electrical connections.
Iron and Steel are both hard and strong. Therefore they are used to construct bridges and buildings. A disadvantage of using Iron is that it tends to rust, whereas most steels rust, they can be formulated to be rust free.
Aluminium is a good conductor of heat and is malleable. It is used to make saucepans and thin foil, and also aeroplane bodies as it is very light.

[edit] Chemical properties of metals

The black surface is lead oxide. The white surface is the lead viewed when the lead oxide is scratched.

Many substances on the Earth's surface will at sometime come in contact with air, water or acids. Therefore the shiny surface of most metals becomes dull in time. This is due to a slow chemical reaction between the surface of the metal and oxygen in the air. The reaction forms only one product; a surface coating of the metal oxide. The general word equation is:

metal+oxygen → metal oxide

For example: The dull appearance of the metal lead is due to a coating of lead oxide.

lead+oxygen → lead oxide

If the surface is scratched then the shiny lead metal can be seen underneath.

Heating can speed up the reaction with oxygen. If a piece of copper is heated it quickly becomes coated in black copper oxide. The word equation is:

copper + oxygen → copper oxide