Rn

Radon

Identification

CAS Number: 10043-92-2

Discovery Year: 1898

Discoverer: Fredrich Ernst Dorn

Discovery Location: Germany

Properties

Atomic Mass: 222 →Density: 0.009074 g/cm³ →

Crust Abundance: 4e-13 mg/kg

Crystal Structure: FCC

Atomic Dimensions

Atomic Radius (Rahm): 243.00000000000003 pm

Covalent Radius: 150 pm →

Van der Waals Radius: 220.00000000000003 pm

Thermodynamics

Melting Point: 202 K →Boiling Point: 211.4 K →Specific Heat: 0.094 J/(g·K) →Thermal Conductivity: 0.0036 W/(m·K) →Heat of Vaporization: 18.1 kJ/mol →

Electronic Structure

Electron Config: [Xe] 4f14 5d10 6s2 6p6

Block: p

Period: 6 →Group: 18 →

Oxidation States: null

Abundance & Geochemistry

Crust Abundance: 4e-13 mg/kg

Sea Abundance: 6e-16 mg/L

Geochemical Class: U/Th decay series

Goldschmidt Class: synthetic

About

Colorless radioactive gaseous element, belongs to the noble gases. Of the twenty known isotopes, the most stable is Rn-222 with a half-life of 3.8 days. Formed by the radioactive decay of Radium-226. Radon itself decays into Polonium. Used in radiotherapy. As a noble gas, it is effectively inert, though radon fluoride has been synthesized. First isolated in 1908 by Ramsey and Gray.

Isotopes

Rn-210 210 ☢ 2.40 h

Rn-211 211 ☢ 14.6 h

Rn-222 222 ☢ 3.82 d