Helium vs Cadmium
| Property | He Helium | Cd Cadmium |
|---|---|---|
| Atomic number | 2 | 48 |
| Symbol | He | Cd |
| Name | Helium | Cadmium |
| Category | noble-gas | transition-metal |
| Standard Atomic Weight | 4.002602 u | 112.414 u |
| Period | 1 | 5 |
| Group | 18 | 12 |
| Block | s | s |
| Phase at STP | gas | solid |
| Electron configuration | 1s2 | [Kr]5s24d10 |
| Oxidation states | [0] | [-2, 1, 2] |
| Electronegativity (Pauling) | N/A | 1.69 |
| Electron affinity | -0.5 eV | -0.7 eV |
| Density | 0.1785 kg/m³ | 8690 kg/m³ |
| Melting point | -272.2 °C | 321.07 °C |
| Boiling point | -268.93 °C | 766.85 °C |
| Discovery year | 1868 | 1817 |