Radium (Ra)
Radium (Ra) is element 88, an alkaline earth metal. Atomic mass 226, configuration [Rn] 7s². Properties, isotopes, oxidation states, uses and history, with an interactive 3D atom model.
Key facts
| Atomic number | 88 |
|---|---|
| Symbol | Ra |
| Standard atomic weight | 226 |
| Category | Alkaline Earth Metal |
| Group | 2 |
| Period | 7 |
| State at room temperature | Solid |
| Electron configuration | [Rn] 7s² |
| Valence electrons | 2 |
| Common oxidation states | +2 |
| Common ions | No common ions |
| Electronegativity (Pauling) | 0.9 |
| First ionization energy | 509 kJ/mol |
| Electron affinity | 9.65 kJ/mol |
| Atomic radius | 215 pm |
| Density | ~5 g/cm³ |
| Melting point | ~700°C |
| Boiling point | ~1627°C |
Common uses
- Historical glow-in-the-dark paint (banned)
- Cancer treatment (Ra-223)
Where it matters
- Labor Rights ("Radium Girls" poisoning cases)
- History of Oncology
Hazards
- Highly radiotoxic bone seeker (mimics Calcium)
History
| Discovered | 1898 |
|---|---|
| Discovered by | Marie & Pierre Curie |
| Name | Latin radius (ray) |