Niobium vs Francium
| Property | Nb Niobium | Fr Francium |
|---|---|---|
| Atomic number | 41 | 87 |
| Symbol | Nb | Fr |
| Name | Niobium | Francium |
| Category | transition-metal | alkali-metal |
| Standard Atomic Weight | 92.90637 u | 223 u |
| Period | 5 | 7 |
| Group | 5 | 1 |
| Block | s | s |
| Phase at STP | solid | solid |
| Electron configuration | [Kr]5s14d4 | [Rn]7s1 |
| Oxidation states | [-3, -1, 0, 1, 2, 3, 4, 5] | [1] |
| Electronegativity (Pauling) | 1.6 | 0.7 |
| Electron affinity | 0.893 eV | 0.491 eV |
| Density | 8570 kg/m³ | 1870 kg/m³ |
| Melting point | 2476.85 °C | 26.85 °C |
| Boiling point | 4743.85 °C | -273.15 °C |
| Discovery year | 1801 | 1939 |