Helium vs Cerium
| Property | He Helium | Ce Cerium |
|---|---|---|
| Atomic number | 2 | 58 |
| Symbol | He | Ce |
| Name | Helium | Cerium |
| Category | noble-gas | lanthanide |
| Standard Atomic Weight | 4.002602 u | 140.116 u |
| Period | 1 | 6 |
| Group | 18 | N/A |
| Block | s | s |
| Phase at STP | gas | solid |
| Electron configuration | 1s2 | [Xe]6s24f15d1 |
| Oxidation states | [0] | [1, 2, 3, 4] |
| Electronegativity (Pauling) | N/A | 1.12 |
| Electron affinity | -0.5 eV | 0.955 eV |
| Density | 0.1785 kg/m³ | 6770 kg/m³ |
| Melting point | -272.2 °C | 797.85 °C |
| Boiling point | -268.93 °C | 3423.85 °C |
| Discovery year | 1868 | 1801 |