Iridium vs Protactinium
| Property | Ir Iridium | Pa Protactinium |
|---|---|---|
| Atomic number | 77 | 91 |
| Symbol | Ir | Pa |
| Name | Iridium | Protactinium |
| Category | transition-metal | actinide |
| Standard Atomic Weight | 192.217 u | 231.03588 u |
| Period | 6 | 7 |
| Group | 9 | N/A |
| Block | s | s |
| Phase at STP | solid | solid |
| Electron configuration | [Xe]6s24f145d7 | [Rn]7s25f26d1 |
| Oxidation states | [-3, -2, -1, 1, 2, 3, 4, 5, 6, 7, 8, 9] | [2, 3, 4, 5] |
| Electronegativity (Pauling) | 2.2 | 1.5 |
| Electron affinity | 1.565 eV | 0.123 eV |
| Density | 2.256220e+4 kg/m³ | 1.537000e+4 kg/m³ |
| Melting point | 2445.85 °C | 1571.85 °C |
| Boiling point | 4427.85 °C | -273.15 °C |
| Discovery year | 1803 | 1913 |