Helium
Noble gas| Atomic number | 2 |
|---|---|
| Category | Noble gas |
| Atomic mass | 4.003 |
| Electron configuration | 1s² |
| Oxidation states | 0 |
| Melting point | -272 °C |
| Boiling point | -269 °C |
| Density | 0 g/cm³ |
| Crystal structure | Close-packed hexagonal |
| Group | 18 |
| Period | 1 |
| Block | s |
| Discovered | 1,868 |
| Crustal abundance | 0.008 ppm |