Oxygen vs Promethium
| Property | O Oxygen | Pm Promethium |
|---|---|---|
| Atomic number | 8 | 61 |
| Symbol | O | Pm |
| Name | Oxygen | Promethium |
| Category | nonmetal | lanthanide |
| Standard Atomic Weight | 15.9994 u | 145 u |
| Period | 2 | 6 |
| Group | 16 | N/A |
| Block | p | s |
| Phase at STP | gas | solid |
| Electron configuration | [He]2s22p4 | [Xe]6s24f5 |
| Oxidation states | [-2, -1, 0, 1, 2] | [2, 3] |
| Electronegativity (Pauling) | 3.44 | N/A |
| Electron affinity | 1.4611 eV | 0.129 eV |
| Density | 1.429 kg/m³ | 7260 kg/m³ |
| Melting point | -218.79 °C | 1041.85 °C |
| Boiling point | -182.95 °C | 2999.85 °C |
| Discovery year | 1771 | 1902 |