Rubidium vs Protactinium
| Property | Rb Rubidium | Pa Protactinium |
|---|---|---|
| Atomic number | 37 | 91 |
| Symbol | Rb | Pa |
| Name | Rubidium | Protactinium |
| Category | alkali-metal | actinide |
| Standard Atomic Weight | 85.4678 u | 231.03588 u |
| Period | 5 | 7 |
| Group | 1 | N/A |
| Block | s | s |
| Phase at STP | solid | solid |
| Electron configuration | [Kr]5s1 | [Rn]7s25f26d1 |
| Oxidation states | [-1, 1] | [2, 3, 4, 5] |
| Electronegativity (Pauling) | 0.82 | 1.5 |
| Electron affinity | 0.4859 eV | 0.123 eV |
| Density | 1530 kg/m³ | 1.537000e+4 kg/m³ |
| Melting point | 39.31 °C | 1571.85 °C |
| Boiling point | 687.85 °C | -273.15 °C |
| Discovery year | 1861 | 1913 |