Periodic Table of Elements




Radium was discovered by Marie Sklodowska-Curie and her husband Pierre on December 21, 1898 in a uraninite sample.

Name: Radium
Symbol: Ra
Atomic number: 88
Atomic weight: 226.03
State: solid
Group, period, block: 2, 7, s
Color: silvery white metallic
Classification: alkaline earth metal
Electron configuration: 7s2

Physical properties

Density: 5.5 g/cm-3
Melting point: 973 K,700 C,1292 F
Boiling point: 2010 K,1737 C,3158.6 F

Atomic properties

Oxidation states: 2
Electronegativity: 0.9 (Pauling scale)
Ionization energies: 1st: 509.3 kJmol-1
Covalent radius: 2212 pm
Van der Waals radius: 283 pm
  • Ra
  • Electron Configuration


There are four naturally occurring isotopes of radium exist, 223Ra, 224Ra, 226Ra, and 228Ra.