Most metals are found in the Earth’s crust combined with other elements. Such compounds are found in rocks called ore, rocks from which it is worthwhile to extract a metal.
A few very unreactive metals, such as gold, are found native which means they are found in the Earth’s crust as the uncombined element.
Extraction of a metal from its ore typically involves removing oxygen from metal oxides.
If the ore contains a metal which is below carbon in the reactivity series then the metal is extracted by reaction with carbon in a displacement reaction.
If the ore contains a metal which is above carbon in the reactivity series then electrolysis (or reaction with a more reactive metal) is used to extract the metal.
Extraction of a metal from its ore typically involves removing oxygen from metal oxides.
If the ore contains a metal which is below carbon in the reactivity series then the metal is extracted by reaction with carbon in a displacement reaction.
If the ore contains a metal which is above carbon in the reactivity series then electrolysis (or reaction with a more reactive metal) is used to extract the metal.
| Aluminium | |
|---|---|
| Use | Property |
| Aircrafts and cans | Low density / resists corrosion |
| Power cables | Conducts electricity / ductile |
| Pots and pans | Low density / strong (when alloyed) / good conductor of electricity and heat |
Aluminium resists corrosion because it has a very thin, but very strong, layer of aluminium oxide on the surface.
| Copper | |
|---|---|
| Use | Property |
| Electrical wires | very good conductor of electricity and ductile |
| Pots and pans | very good conductor of heat / very unreactive / malleable |
| Water pipes | unreactive / malleable |
| Surfaces in hospitals | antimicrobial properties / malleable |
| Iron | |
|---|---|
| Use | Property |
| Buildings | Strong |
| Saucepans | Conducts heat / high melting point / malleable |
| Steel | ||
|---|---|---|
| Type of steel | Iron mixed with | Some uses |
| Mild steel | up to 0.25% carbon | nails, car bodies, ship building, girders |
| High-carbon steel | 0.6%-1.2% carbon | cutting tools, masonry nails |
| Stainless steel | Chromium (and nickel) | cutlery, cooking utensils, kitchen sinks |
Mild steel is a strong material that can easily be hammered into various shapes (malleable). It rusts easily.
High-carbon steel is harder than mild steel but more brittle (not as malleable).
Stainless steel forms a strong, protective oxide layer so is very resistant to corrosion.
An alloy is a mixture of a metal with, usually, other metals or carbon.
For example, brass is a alloy of copper and zinc, and steel is an alloy of iron and carbon.
Alloys are harder than the individual pure metals from which they are made.
In an alloy, the different elements have slightly different sized atoms. This breaks up the regular lattice arrangement and makes it more difficult for layers of ions to slide over each other.
