Helium vs Cobalt
| Property | He Helium | Co Cobalt |
|---|---|---|
| Atomic number | 2 | 27 |
| Symbol | He | Co |
| Name | Helium | Cobalt |
| Category | noble-gas | transition-metal |
| Standard Atomic Weight | 4.002602 u | 58.933194 u |
| Period | 1 | 4 |
| Group | 18 | 9 |
| Block | s | s |
| Phase at STP | gas | solid |
| Electron configuration | 1s2 | [Ar]4s23d7 |
| Oxidation states | [0] | [-3, -1, 0, 1, 2, 3, 4, 5] |
| Electronegativity (Pauling) | N/A | 1.88 |
| Electron affinity | -0.5 eV | 0.661 eV |
| Density | 0.1785 kg/m³ | 8860 kg/m³ |
| Melting point | -272.2 °C | 1494.85 °C |
| Boiling point | -268.93 °C | 2926.85 °C |
| Discovery year | 1868 | 1735 |