Actinium vs Einsteinium
| Property | Ac Actinium | Es Einsteinium |
|---|---|---|
| Atomic number | 89 | 99 |
| Symbol | Ac | Es |
| Name | Actinium | Einsteinium |
| Category | actinide | actinide |
| Standard Atomic Weight | 227 u | 252 u |
| Period | 7 | 7 |
| Group | N/A | N/A |
| Block | s | s |
| Phase at STP | solid | solid |
| Electron configuration | [Rn]7s26d1 | [Rn]7s25f11 |
| Oxidation states | [3] | [2, 3, 4] |
| Electronegativity (Pauling) | 1.1 | 1.3 |
| Electron affinity | 0.35 eV | -0.3 eV |
| Density | 1.007000e+4 kg/m³ | 8840 kg/m³ |
| Melting point | 1050.85 °C | 859.85 °C |
| Boiling point | 3197.85 °C | -273.15 °C |
| Discovery year | 1899 | 1952 |