Rn
Radon
Atomic number: 86Mass: 222 uCategory: Noble Gas
About Radon
Radon is a radioactive, colourless, odourless, tasteless noble gas. It occurs naturally from the decay of radium. It is the heaviest naturally occurring noble gas. Radon seeps into buildings through soil and rock and is the second leading cause of lung cancer after smoking.
Properties
Period
6
Group
18
Block
P
Category
Noble Gas
Electronegativity
N/A
Ionization Energy
1037 kJ/mol
Melting Point
202 K (-71°C)
Boiling Point
212 K (-62°C)
Density
9.730 g/L
Oxidation States
+2
Electron Configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p⁶
[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶
Shell 1:2e⁻
Shell 2:8e⁻
Shell 3:18e⁻
Shell 4:32e⁻
Shell 5:18e⁻
Shell 6:8e⁻
Real-World Uses
Radon therapy (historical)
Earthquake prediction
Lung cancer radiotherapy
Research
Geothermal studies
Fun Fact
Radon is the second leading cause of lung cancer after smoking — it seeps invisibly from rocks and soil into homes, and you can't smell or see it!