When metals react with non-metals, electrons are transferred from the metal atoms to the non-metal atoms, forming ions. The resulting compound is called an ionic compound.

Reactions between metals and non-metals include:

• sodium + chlorine → sodium chloride
• magnesium + oxygen → magnesium oxide
• calcium + chlorine → calcium chloride
• lithium + oxygen → lithium oxide

In all of these reactions, the metal atoms give electrons to the non-metal atoms. The metal atoms become positive ions and the non-metal atoms become negative ions.

There is a strong electrostatic force of attraction between these oppositely charged ions – this is called an ionic bond.

The slideshow shows ionic bonds being formed in sodium chloride, magnesium oxide, calcium chloride and lithium chloride.