Rn
Radon
Element 86 · Noble gas
Radon (Rn)
Radon is a colourless, radioactive noble gas that seeps from rocks and soil. It can build up in basements.
- Noble gas
- Period 6
- Group 18
- p-block
- gas at room temperature
- ☢ Radioactive
Key properties
- Atomic mass
- [222]
- u
- Electron configuration
- [Xe] 4f14 5d10 6s2 6p6
- Melting point
- -71.1 °C
- 202 K
- Boiling point
- -61.7 °C
- 211.45 K
- Density
- 9.73 g/L
- Electronegativity
- 2.2
- Pauling
- Atomic radius
- 220 pm
- van der Waals
- 1st ionisation energy
- 10.745 eV
Compare with every element:Electronegativity chartAtomic radius chartIonisation energy chartDensity chart of the elementsMelting point chartElectron configuration chart
Did you know?
Notable facts about radon
- 01
Radon is the second leading cause of lung cancer after smoking.
- 02
It is the densest gas known at room temperature.
- 03
Radon levels in groundwater have been studied as a possible earthquake precursor.
Applications
What is radon used for?
- Radiotherapy (historically)
- Geological tracer studies
- Hydrology research
History
Discovery & name origin
Discovered by
Year
Where
Germany
Name origin
From radium, which gives off the gas as it decays.
Atomic structure
Atomic properties
Atomic structure
Atomic properties
- Atomic number
- 86
- Atomic mass
- [222] u
- Group
- 18
- Period
- 6
- Block
- p-block
- Electron configuration
- [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
- Electronegativity (Pauling)
- 2.2
- Electron affinity
- —
- Atomic radius (van der Waals)
- 220 pm
- Stable isotopes
- None — all isotopes are radioactive
Oxidation states
Highlighted: common oxidation states (0).
Physical
Physical properties & colour
Physical
Physical properties & colour
- State at 20 °C
- Gas
- Melting point
- 202 K · -71.1 °C · -96.1 °F
- Boiling point
- 211.45 K · -61.7 °C · -79.1 °F
- Density
- 9.73 g/L
- Molar heat capacity
- —
- Appearance
- Colourless gas, occasionally glows green or red in discharge tubes
- CPK model colour
- Copied
The CPK colour is the convention used for this element’s atoms in molecular models.
FAQ
Radon questions
What is Rn on the periodic table?
Rn is the symbol for radon, element 86 on the periodic table. It sits in group 18, period 6, in the noble gas category, and has an atomic mass of [222].
What is the atomic number of radon?
Radon has atomic number 86, so every radon atom has 86 protons in its nucleus. Its symbol is Rn and its atomic mass is [222].
Who discovered radon?
Radon was discovered by Friedrich Ernst Dorn in 1900 (Germany). The name comes from from radium, which gives off the gas as it decays.
What is radon used for?
Radon is used for: radiotherapy (historically); geological tracer studies; hydrology research.
Is radon a metal?
No. Radon is classed as a noble gas.
What is the electron configuration of radon?
The electron configuration of radon is [Xe] 4f14 5d10 6s2 6p6. Its 86 electrons are arranged in shells as 2, 8, 18, 32, 18, 8.