Periodic TableAll elementsRadon
No. 086
Rn
222 u
Element · Noble Gas

Radon

Radon (氡, symbol Rn) is chemical element number 86, a Noble Gas in period 6, group 18 of the periodic table, with a standard atomic weight of about 222. Radioactive noble gas. Major source of natural radiation exposure for humans.

Period 6Group 18[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶

Properties

Atomic number86
SymbolRn
Atomic mass222 u
CategoryNoble Gas
Period6
Group18
Electron configuration[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶
Electronegativity2.2
Covalent radius150 pm
Density0.00973 g/cm³
Melting point202 K
Boiling point211.3 K
DiscoveryFriedrich Ernst Dorn, 1900

Overview

Radioactive noble gas. Major source of natural radiation exposure for humans. Radon (Rn) is a Noble Gas with atomic number 86, located in period 6, group 18. As a noble gas it has a full outer shell, is extremely unreactive, and exists as a monatomic gas at room temperature.

Its electron configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶, with 8 electrons in the outer shell, and an electronegativity of about 2.2 (Pauling). Around 25 °C it is usually a gas (a very low melting point); it melts near 202 K (-71.1 °C), boils near 211.3 K (-61.8 °C), has a density around 0.00973 g/cm³.

In industry and daily life it turns up in Research and Industrial Gas. It is regarded as a high-hazard element, so handle it with appropriate care. It was first described by Friedrich Ernst Dorn in 1900.

Electron shells

Rn86

Electrons per shell: 2 · 8 · 18 · 32 · 18 · 8

Main uses

Hazard

HighRadioactive

Compounds containing Radon

No compounds in this knowledge base contain Radon yet.

Data sources

Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.