Rubidium vs Radium
| Property | Rb Rubidium | Ra Radium |
|---|---|---|
| Atomic number | 37 | 88 |
| Symbol | Rb | Ra |
| Name | Rubidium | Radium |
| Category | alkali-metal | alkaline-earth-metal |
| Standard Atomic Weight | 85.4678 u | 226 u |
| Period | 5 | 7 |
| Group | 1 | 2 |
| Block | s | s |
| Phase at STP | solid | solid |
| Electron configuration | [Kr]5s1 | [Rn]7s2 |
| Oxidation states | [-1, 1] | [2] |
| Electronegativity (Pauling) | 0.82 | 0.9 |
| Electron affinity | 0.4859 eV | 0.096 eV |
| Density | 1530 kg/m³ | 5000 kg/m³ |
| Melting point | 39.31 °C | 699.85 °C |
| Boiling point | 687.85 °C | 1139.85 °C |
| Discovery year | 1861 | 1898 |