86
Rn
Radon
222
Radon (Rn)
Noble GasGroup 18Period 6p-block-blockRadioactive
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.
Latin name: Radon
Atomic Number
86
Atomic Mass
222 g/mol
Phase (STP)
Gas
Electron Config.
[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶
General
SymbolRn
Atomic Number86
Atomic Mass222 g/mol
CategoryNoble Gas
Group18
Period6
Blockp-block
Electron Configuration[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶
Valence Electrons8
Colourcolorless
Appearancecolorless gas, occasionally glows green or red in discharge tubes
CAS NumberCAS10043-92-2
Physical Properties
Phase (STP)Gas
Density0.00973 g/cm³
Melting Point-71.15°C · -96.07°F · 202.00 K
Boiling Point-61.65°C · -78.97°F · 211.50 K
Atomic Properties
Atomic Radius220 pm
Ionization Energy1037 kJ/mol
Oxidation States+2, 0
Ion ChargeRn2+
Crystal Structure
Crystal Structureface-centered cubic (solid)
Nuclear & Hazards
RadioactiveYes
Half-life3.823 days (Rn-222)
Abundance
In Universe0.000000000001%
In Earth's Crust0.000000000001%
Discovery & History
Discovery Year1900
Discovered ByFriedrich Ernst Dorn
Country of DiscoveryGermany
Isotopes of Radon
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Rn-210 | — | 2.4 hours | α |
| Rn-211 | — | 14.6 hours | α, EC |
| Rn-220 | — | 55.6 seconds | α |
| Rn-222 | — | 3.8235 days | α |