Oxidation

Combustion is an example of a type of reaction called oxidation. In an oxidation reaction, a substance gains oxygen. Metals and non-metals can take part in oxidation reactions.

Metals

Metals react with oxygen in the air to produce metal oxides. For example, magnesium reacts with oxygen to produce magnesium oxide when it is heated in air:

magnesium + oxygen → magnesium oxide

2Mg + O2 → 2MgO

Magnesium ribbon burning
Magnesium reacts vigorously with oxygen to produce magnesium oxide

Metal oxides are bases they react with acids and neutralise them. Some metal oxides dissolve in water to produce alkaline solutions.

Non-metals

Non-metals react with oxygen in the air to produce non-metal oxides. Here are two examples for the non-metals carbon and sulfur.

Carbon reacts with oxygen to form carbon dioxide:

carbon + oxygen → carbon dioxide

C + O2 → CO2

Sulfur burns reacts with oxygen to form sulfur dioxide:

sulfur + oxygen → sulfur dioxide

S + O2 → SO2

Non-metal oxides are acids – they react with bases and neutralise them. Some non-metal oxides dissolve in water to produce acidic solutions.