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88
Ra
[226]
Radium
Alkaline earth metals · Group 2 · Period 7
Atomic properties
| Atomic number | 88 |
|---|---|
| Symbol | Ra |
| Standard atomic weight | [226] |
| Classification | Alkaline earth metals |
| Group | 2 |
| Period | 7 |
| Block | s-block |
| Electron configuration | [Rn] 7s2 |
| Electronegativity (Pauling) | 0.90 |
| Common oxidation states | +2 |
Physical properties
| Phase at 20 °C | Solid |
|---|---|
| Density | 5.5 g/cm³ |
| Melting point | 700 °C |
| Boiling point | 1737 °C |
| Discovered | 1898 |
| CAS number | — |