Niobium vs Protactinium
| Property | Nb Niobium | Pa Protactinium |
|---|---|---|
| Atomic number | 41 | 91 |
| Symbol | Nb | Pa |
| Name | Niobium | Protactinium |
| Category | transition-metal | actinide |
| Standard Atomic Weight | 92.90637 u | 231.03588 u |
| Period | 5 | 7 |
| Group | 5 | N/A |
| Block | s | s |
| Phase at STP | solid | solid |
| Electron configuration | [Kr]5s14d4 | [Rn]7s25f26d1 |
| Oxidation states | [-3, -1, 0, 1, 2, 3, 4, 5] | [2, 3, 4, 5] |
| Electronegativity (Pauling) | 1.6 | 1.5 |
| Electron affinity | 0.893 eV | 0.123 eV |
| Density | 8570 kg/m³ | 1.537000e+4 kg/m³ |
| Melting point | 2476.85 °C | 1571.85 °C |
| Boiling point | 4743.85 °C | -273.15 °C |
| Discovery year | 1801 | 1913 |