Atomic Radii
Atomic Radius
Bohr Radius
Covalent Radius
Van der Waals
| Helium | |
| Electron Configuration | 2 |
| Electron Configuration | 1s2 |
| Electronegativity | ? |
| Enthalpy of Fusion | 0.021 kJ mol-1 |
| Enthalpy of Vaporisation | 0.082 kJ mol-1 |
| Heat Capacity | 20.786 J mol-1 K-1 |
| Thermal Conductivity | 151.3 W m-1 K-1 |
| Thermal Expansion | ? μm m-1 K-1 |
| Magnetic ordering | No data |
| Atomic Radii |
|
| Atomic Radius
|
31 pm |
| Bohr Radius
|
31 pm |
| Covalent Radius
|
32 pm |
| Van der Waals
|
140 pm |
Ionisation Energies (kJ mol-1)  |
|
| M - M+ |
2372.3 |
| M+ - M2+ |
5250.4 |