Arsenic vs Protactinium
| Property | As Arsenic | Pa Protactinium |
|---|---|---|
| Atomic number | 33 | 91 |
| Symbol | As | Pa |
| Name | Arsenic | Protactinium |
| Category | metalloid | actinide |
| Standard Atomic Weight | 74.921595 u | 231.03588 u |
| Period | 4 | 7 |
| Group | 15 | N/A |
| Block | p | s |
| Phase at STP | solid | solid |
| Electron configuration | [Ar]4s23d104p3 | [Rn]7s25f26d1 |
| Oxidation states | [-3, -2, -1, 0, 1, 2, 3, 4, 5] | [2, 3, 4, 5] |
| Electronegativity (Pauling) | 2.18 | 1.5 |
| Electron affinity | 0.81 eV | 0.123 eV |
| Density | 5776 kg/m³ | 1.537000e+4 kg/m³ |
| Melting point | 816.85 °C | 1571.85 °C |
| Boiling point | 613.85 °C | -273.15 °C |
| Discovery year | 1250 | 1913 |