Properties of metals and non-metals

Differences in chemical properties

Most elements are metals. In their chemical reactions, metal atoms lose electrons to form positive ions. For example:

  • when magnesium burns in air, each atom loses two electrons to form a Mg2+ ion
  • when sodium reacts with chlorine, each sodium atom loses one electron to form a Na+ ion
How a sodium atom becomes a sodium ion when it loses an electronA sodium atom, Na, forms a Na+ ion by losing an electron.

Elements that do not form positive ions in their chemical reaction are non-metals.

For more information on ions, see the study guide on ions.

The chemical properties of the compounds of metal and non-metal elements are also different:

  • most metal oxides are basic
  • most non-metal oxides are acidic

Differences in physical properties

Metal and non-metal elements have different physical properties:

  • most metals have high melting and boiling points
  • most non-metals have low melting and boiling points

The table shows some other differences in physical properties of metals and non-metals, when solid.

Properties of a typical metal (when solid)Properties of a typical non-metal (when solid)
Good conductor of electricity Poor conductor of electricity
Good conductor of heatPoor conductor of heat
High densityLow density