Group 0: Noble gases
Noble gases are colourless elements in group 0. They do not react easily because their atoms already have full outer electron shells.
Noble gases are inert, meaning that they do not react. Due to their inert nature, noble gases are usually found as individual atoms.
They are often used to create an inert atmosphere that prevents unwanted reactions.
Neon and argon are used in traditional light bulbs. This prevents oxidation of the heated tungsten wire which would oxidise when exposed to air.
Helium is used in balloons. Helium is lighter than air, which causes balloons to rise. Helium is preferred over hydrogen (which is even lighter) because hydrogen is highly reactive (and could cause an explosion).
Argon is used in steel production to displace gases that could cause unwanted oxidation of the steel.