Non-metals are very important elements. Most of our body is composed of non-metals.

Unlike the metals there are some non-metals that are gases at room temperature. For example, oxygen, hydrogen, nitrogen, chlorine, fluorine and all the elements in group VIII of the periodic table are gases at room temperature. Bromine is the only non-metal that is a liquid at room temperature. The rest of the non-metals are solids at room temperature.

The solid non-metals are usually brittle and dull.

They usually have low melting pointsand do not conduct electricity.

Carbon is an unusual non-metal because it can be found in more than one form. Both graphite and diamond are carbon, even though they do not have all the same properties. They both have very high melting points and graphite is a very good conductor of electricity. Diamonds are very hard and shiny and graphite is brittle and dull.

Name	Properties	Uses
Chlorine	Yellow green colour Reactive Unpleasant odour	Insecticides Bleach Water treatment
Helium	Colourless Unreactive	Balloons Welding Airships
Phosphorus	Red Poisonous	Fertilisers Match heads

 

Metalloids

Metalloids or semi-metals are those elements which have combinations of metallic and non-metallic properties.

Silicon is a metalloid it is used to make semiconductors, in solar cells and in silicon rubber.