Hafnium vs Roentgenium
| Property | Hf Hafnium | Rg Roentgenium |
|---|---|---|
| Atomic number | 72 | 111 |
| Symbol | Hf | Rg |
| Name | Hafnium | Roentgenium |
| Category | transition-metal | transition-metal |
| Standard Atomic Weight | 178.49 u | 281 u |
| Period | 6 | 7 |
| Group | 4 | 11 |
| Block | s | s |
| Phase at STP | solid | N/A |
| Electron configuration | [Xe]6s24f145d2 | [Rn] 7s2 5f14 6d9(predicted) |
| Oxidation states | [-2, 0, 1, 2, 3, 4] | [-1, 1, 3, 5] |
| Electronegativity (Pauling) | 1.3 | N/A |
| Electron affinity | 0.178 eV | 1.6 eV |
| Density | 1.330000e+4 kg/m³ | 2.870000e+4 kg/m³ |
| Melting point | 2232.85 °C | -273.15 °C |
| Boiling point | 4602.85 °C | -273.15 °C |
| Discovery year | 1911 | 1994 |