88
226.00
Ra
Radium
Identification
CAS Number: 7440-14-4
Discovery Year: 1898
Discoverer: Pierre and Marie Curie
Discovery Location: France
Properties
Atomic Dimensions
Atomic Radius: 215 pm →
Atomic Radius (Rahm): 292 pm
Covalent Radius: 221 pm →Van der Waals Radius: 283 pm
Atomic Volume: 45 cm³/mol
Thermodynamics
Electronic Structure
Electron Config: [Rn] 7s2
Block: s
Period: 7 →Group: 2 →Electronegativity: 0.9 →Electron Affinity: 0.1 eV →Oxidation States: +2
Abundance & Geochemistry
Crust Abundance: 9e-7 mg/kg
Sea Abundance: 8.9e-11 mg/L
Geochemical Class: U/Th decay series
Goldschmidt Class: litophile
About
Radioactive metallic transuranic element, belongs to group 2 of the periodic table. Most stable isotope, Ra-226 has a half-life of 1602 years, which decays into radon. Isolated from pitchblende in 1898 Marie and Pierre Curie.
Isotopes
Ra-226 226 ☢ 1.60e+3 a
Ra-228 228 ☢ 5.75 a
