Protactinium vs Nobelium
| Property | Pa Protactinium | No Nobelium |
|---|---|---|
| Atomic number | 91 | 102 |
| Symbol | Pa | No |
| Name | Protactinium | Nobelium |
| Category | actinide | actinide |
| Standard Atomic Weight | 231.03588 u | 259 u |
| Period | 7 | 7 |
| Group | N/A | N/A |
| Block | s | s |
| Phase at STP | solid | solid |
| Electron configuration | [Rn]7s25f26d1 | [Rn]7s25f14 |
| Oxidation states | [2, 3, 4, 5] | [2, 3] |
| Electronegativity (Pauling) | 1.5 | 1.3 |
| Electron affinity | 0.123 eV | -2.36 eV |
| Density | 1.537000e+4 kg/m³ | 9900 kg/m³ |
| Melting point | 1571.85 °C | 826.85 °C |
| Boiling point | -273.15 °C | -273.15 °C |
| Discovery year | 1913 | 1957 |