Arsenic vs Promethium
| Property | As Arsenic | Pm Promethium |
|---|---|---|
| Atomic number | 33 | 61 |
| Symbol | As | Pm |
| Name | Arsenic | Promethium |
| Category | metalloid | lanthanide |
| Standard Atomic Weight | 74.921595 u | 145 u |
| Period | 4 | 6 |
| Group | 15 | N/A |
| Block | p | s |
| Phase at STP | solid | solid |
| Electron configuration | [Ar]4s23d104p3 | [Xe]6s24f5 |
| Oxidation states | [-3, -2, -1, 0, 1, 2, 3, 4, 5] | [2, 3] |
| Electronegativity (Pauling) | 2.18 | N/A |
| Electron affinity | 0.81 eV | 0.129 eV |
| Density | 5776 kg/m³ | 7260 kg/m³ |
| Melting point | 816.85 °C | 1041.85 °C |
| Boiling point | 613.85 °C | 2999.85 °C |
| Discovery year | 1250 | 1902 |