Helium vs Lithium
| Property | He Helium | Li Lithium |
|---|---|---|
| Atomic number | 2 | 3 |
| Symbol | He | Li |
| Name | Helium | Lithium |
| Category | noble-gas | alkali-metal |
| Standard Atomic Weight | 4.002602 u | 6.9675 u |
| Period | 1 | 2 |
| Group | 18 | 1 |
| Block | s | s |
| Phase at STP | gas | solid |
| Electron configuration | 1s2 | [He]2s1 |
| Oxidation states | [0] | [1] |
| Electronegativity (Pauling) | N/A | 0.98 |
| Electron affinity | -0.5 eV | 0.61804 eV |
| Density | 0.1785 kg/m³ | 534 kg/m³ |
| Melting point | -272.2 °C | 180.5 °C |
| Boiling point | -268.93 °C | 1341.85 °C |
| Discovery year | 1868 | 1817 |