Helium vs Xenon
| Property | He Helium | Xe Xenon |
|---|---|---|
| Atomic number | 2 | 54 |
| Symbol | He | Xe |
| Name | Helium | Xenon |
| Category | noble-gas | noble-gas |
| Standard Atomic Weight | 4.002602 u | 131.293 u |
| Period | 1 | 5 |
| Group | 18 | 18 |
| Block | s | p |
| Phase at STP | gas | gas |
| Electron configuration | 1s2 | [Kr]5s24d105p6 |
| Oxidation states | [0] | [0, 2, 4, 6, 8] |
| Electronegativity (Pauling) | N/A | 2.6 |
| Electron affinity | -0.5 eV | -0.8 eV |
| Density | 0.1785 kg/m³ | 5.887 kg/m³ |
| Melting point | -272.2 °C | -111.79 °C |
| Boiling point | -268.93 °C | -108.1 °C |
| Discovery year | 1868 | 1898 |