Potassium vs Rubidium
Pick up to 3 elements and see how they stack up.
| Property | Potassium | Rubidium |
|---|---|---|
| Atomic number | 19 | 37 |
| Atomic mass | 39.098 | 85.468 |
| Electronegativity | 0.82 | 0.82 |
| Melting point | 336.7 K (63.6 °C) | 312.45 K (39.3 °C) |
| Boiling point | 1,032 K (758.8 °C) | 961 K (687.8 °C) |
| Density | 0.862 g/cm³ | 1.532 g/cm³ |
| Atomic radius | 275 pm | 303 pm |
| Ionization energy | 4.341 eV | 4.177 eV |
| Discovered | 1807 | 1861 |
| Category | Alkali metal | Alkali metal |
| State at room temp. | Solid | Solid |
| Block | s | s |
| Group | 1 | 1 |
| Period | 4 | 5 |
| Valence electrons | 1 | 1 |
| Common charges | +1 | +1 |
| Electron configuration | [Ar] 4s1 | [Kr] 5s1 |