Hafnium vs Actinium
| Property | Hf Hafnium | Ac Actinium |
|---|---|---|
| Atomic number | 72 | 89 |
| Symbol | Hf | Ac |
| Name | Hafnium | Actinium |
| Category | transition-metal | actinide |
| Standard Atomic Weight | 178.49 u | 227 u |
| Period | 6 | 7 |
| Group | 4 | N/A |
| Block | s | s |
| Phase at STP | solid | solid |
| Electron configuration | [Xe]6s24f145d2 | [Rn]7s26d1 |
| Oxidation states | [-2, 0, 1, 2, 3, 4] | [3] |
| Electronegativity (Pauling) | 1.3 | 1.1 |
| Electron affinity | 0.178 eV | 0.35 eV |
| Density | 1.330000e+4 kg/m³ | 1.007000e+4 kg/m³ |
| Melting point | 2232.85 °C | 1050.85 °C |
| Boiling point | 4602.85 °C | 3197.85 °C |
| Discovery year | 1911 | 1899 |