You're listening to Chemistry in its element brought to you by Chemistry World ... a tiny proportion of a heavier and even less reactive gas is left over. They named this gas argon from the Greek for ...

Argon, krypton and xenon are very unreactive. They replace the air inside the lamp, preventing the metal wire from burning away.

Because many gases, including argon and oxygen ... oxygen is required in high purity for combustion and chemical reactions, whereas in medical settings, concentrated oxygen is vital for treatment ...