Krypton vs Promethium
| Property | Kr Krypton | Pm Promethium |
|---|---|---|
| Atomic number | 36 | 61 |
| Symbol | Kr | Pm |
| Name | Krypton | Promethium |
| Category | noble-gas | lanthanide |
| Standard Atomic Weight | 83.798 u | 145 u |
| Period | 4 | 6 |
| Group | 18 | N/A |
| Block | p | s |
| Phase at STP | gas | solid |
| Electron configuration | [Ar]4s23d104p6 | [Xe]6s24f5 |
| Oxidation states | [0, 1, 2] | [2, 3] |
| Electronegativity (Pauling) | 3 | N/A |
| Electron affinity | -1 eV | 0.129 eV |
| Density | 3.733 kg/m³ | 7260 kg/m³ |
| Melting point | -157.36 °C | 1041.85 °C |
| Boiling point | -153.42 °C | 2999.85 °C |
| Discovery year | 1898 | 1902 |