Helium vs Praseodymium
| Property | He Helium | Pr Praseodymium |
|---|---|---|
| Atomic number | 2 | 59 |
| Symbol | He | Pr |
| Name | Helium | Praseodymium |
| Category | noble-gas | lanthanide |
| Standard Atomic Weight | 4.002602 u | 140.90766 u |
| Period | 1 | 6 |
| Group | 18 | N/A |
| Block | s | s |
| Phase at STP | gas | solid |
| Electron configuration | 1s2 | [Xe]6s24f3 |
| Oxidation states | [0] | [0, 1, 2, 3, 4, 5] |
| Electronegativity (Pauling) | N/A | 1.13 |
| Electron affinity | -0.5 eV | 0.962 eV |
| Density | 0.1785 kg/m³ | 6770 kg/m³ |
| Melting point | -272.2 °C | 930.85 °C |
| Boiling point | -268.93 °C | 3519.85 °C |
| Discovery year | 1868 | 1885 |