Atomic number: 86

Symbol: Rn

Category: noble gas 

Density at 25°C: gas: density: 9.73 kg/m3

Radon is a somewhat more known gaseous element. This radioactive gas is best known for accumulating in basements and indoors. It is of concern to indoor air quality. Radon is the result of decay of thorium and uranium that occurs naturally on Earth.

Use, natural applications or common combinations: 

  • natural occurring source of background radiation (alpha)
  • used to be used for medical treatments
  • can be used to track air masses

Basic characteristics:

  • Standard atomic weight: about 222
  • Melting point: −71.15 °C
  • Boiling point: −61.85 °C
  • Radioactivity: all radioactive
  • 222Rn half life of 3.8235 days to produce (via alpha particle emission) to 218Po which itself is radioactive. but is solid and sticks to surfaces due to static electrical properties.