Oxidation and reduction

== Oxidation== Most metals react with oxygen in the air. Sometimes water also takes part in the reaction. This causes corrosion. For example when iron corrodes to form iron oxide.

iron + oxygen = iron oxide

This is an example of an oxidation reaction. The iron has been oxidised, because it has gained oxygen.

Reduction
Many metal ores contain oxides of the metal. The metal is extracted from its compund by removing oxygen.

aluminium oxide = aluminium + oxygen

This is an example of a reduction reaction. The aluminium oxide has been reduced, because oxygen has been removed from it.