Atomic number 88
Radium
Alkaline earth metal
In the real world
Quick facts
- Atomic mass
- 226.00
- Group
- 2
- Period
- 7
- State (STP)
- solid
- Electronegativity
- 0.90
- Common ox. states
- +2
Properties
Electron configuration
[Rn] 7s²
- Ionization energy
- 509.3 kJ/mol
- Electron affinity
- 9.6 kJ/mol
- Melting point
- 973.00 K (699.9 °C)
- Boiling point
- 2010.00 K (1736.8 °C)
How dangerous is it?
5/5 · Extreme
Once painted onto glow-in-the-dark watch dials, until the workers who licked their brushes fell ill. It is intensely radioactive.
- RadioactiveImmediate and cumulative
It pours out radiation and collects in bones like calcium, causing lasting damage. (devastating once inside the body)
Stored in heavy shielding and handled remotely in licensed labs.
How it bonds
Radium parallels barium: Ra²⁺ in salts, glows in the dark from its own radioactive decay. Marie Curie's discovery; the early 20th-century glow-in-the-dark watch dials that poisoned the 'Radium Girls' factory workers used radium-226.
