86RnRadon222[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶
noble gas

Radon

Radon is a chemical element with symbol Rn and atomic number 86. It is a radioactive, colorless, odorless, tasteless noble gas, occurring naturally as a decay product of radium. Its most stable isotope, 222Rn, has a half-life of 3.8 days.

Electronic structure

A stylized shell model. Electrons are quantum objects, not particles following these literal paths. Sizes and motion are illustrative.

Electrons by shell
Electron configuration
4f14
5d10
6s2
6p6

54 is the [Xe] core total across five shells.

Properties

At a glance

Atomic number
86
Atomic mass
222 u
Phase
Gas
Density
9.73 g/L
Melting point
202 K
Boiling point
211.5 K
First ionization energy
1,037 kJ/mol
Electronegativity
2.2
Electron affinity
-68 kJ/mol
Molar heat capacity
Unavailable
Period
6
Appearance
colorless gas, occasionally glows green or red in discharge tubes

Conditions and isotopes affect measured properties. Some properties of short-lived elements are predicted. Electronegativity uses the Pauling scale.

Keep exploring

Explore the stories, imagery, and reference data in more depth. Properties with no value in the reference are marked unavailable.