When elements react, their atoms complete their outer shells by losing, gaining, or sharing electrons. The atoms of noble gases already have complete outer shells. They have no tendency to lose, gain, or share electrons. This is why the noble gases are inert and do not take part in chemical reactions.
The table summarises the electron arrangements of elements in groups 1, 7 and 0. See that:
The main properties of the noble gases include:
Many uses of the noble gases are linked to one or more of these properties. Argon is used as a ‘shield gas’ when welding pieces of metal together. Argon is:
The hot metal wires will burn away if any oxygen from the air is present in the lamp. Argon, krypton and xenon are very unreactive. They replace the air inside the lamp, preventing the metal wire burning away.