Actinium vs Nobelium
| Property | Ac Actinium | No Nobelium |
|---|---|---|
| Atomic number | 89 | 102 |
| Symbol | Ac | No |
| Name | Actinium | Nobelium |
| Category | actinide | actinide |
| Standard Atomic Weight | 227 u | 259 u |
| Period | 7 | 7 |
| Group | N/A | N/A |
| Block | s | s |
| Phase at STP | solid | solid |
| Electron configuration | [Rn]7s26d1 | [Rn]7s25f14 |
| Oxidation states | [3] | [2, 3] |
| Electronegativity (Pauling) | 1.1 | 1.3 |
| Electron affinity | 0.35 eV | -2.36 eV |
| Density | 1.007000e+4 kg/m³ | 9900 kg/m³ |
| Melting point | 1050.85 °C | 826.85 °C |
| Boiling point | 3197.85 °C | -273.15 °C |
| Discovery year | 1899 | 1957 |