Helium, inflammable and lighter than air, is usually preferred to the more dangerous hydrogen in the filling of balloons, airships and advertising blimps. Like argon, it is used as an inert gas shield in arc welding.
This inertness of the group members tends to determine their uses. Neon, argon, krypton and xenon are all used in electric light bulbs and fluorescent tubes. In discharge tubes - or neon lights - an electric current passed through the gases produces a coloured glow, the exact colour of the glow depending on the particular mixture of gases. The common light bulb contains argon. Being extremely inert, the gases do not react with the light filaments.
The radioactive properties of radon can be exploited in the treatment of cancer.
