086Noble gas · Group 18 · Period 6
Radon
Radon (Rn) is element 86, a noble gas in the p-block — group 18, period 6. It is a gas at room temperature with 6 electron shells (2, 8, 18, 32, 18, 8) and an atomic mass of 222 u.
- Atomic mass
- 222.0 u
- Phase · STP
- gas
- Melting
- 202 K · -71 °C
- Boiling
- 212 K · -62 °C
- Electronegativity
- 2.2
- Density
- 9.73 g/cm³
Photograph — Chemical ELements A Virtual Museum, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0> source: https://images-of-elements.com/radon.php
Emission spectrum
The visible light Radon emits when energised — its unique spectral fingerprint.
Identity
- Atomic number
- 86
- Standard atomic weight
- 222.0 u
- Category
- Noble gas
- Group
- 18 · Noble gases
- Period
- 6
- Block
- p-block
- Oxidation states
- 0
Physical properties
- Melting point
- 202 K · -71 °C
- Boiling point
- 212 K · -62 °C
- Density
- 9.73 g/cm³
- Molar heat capacity
- —
- Atomic radius
- 220 pm
- Electron affinity
- -68 kJ/mol
Atomic structure
86protons
136neutrons
86electrons
8valence e⁻
- Noble-gas notation
- [Xe] 4f14 5d10 6s2 6p6
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6
- Electrons per shell
- 2, 8, 18, 32, 18, 8
Periodic trends
Where Radon ranks across all 118 elements.
Discovery
- Discovered
- 1900
- Discovered by
- Friedrich Ernst Dorn
- Named by
- —
- Appearance
- colorless gas, occasionally glows green or red in discharge tubes