| Helium | |
| Elemental State | He |
| Electron Configuration | 1s2 |
| First Ionization Potential | 24.587 eV |
| Electron Affinity | |
| Z* | 1.688 (Clementi-Raimondi) |
| Pauling Electronegativity | |
| Covalent Radius | |
| Metallic Radius | |
| Ionic Radius | |
| van der Waal's Radius | 1.40 Å |
| Melting Point | less than –272.2 oC at 26 atm |
| Boiling Point | –268.93 oC |
| Density | 0.1785 g/L (0 oC) |
| Other Properties | |