| Helium | |
| Electrons per shell | 2 |
| Electron Configuration | 1s2 ![]() |
| Ground state | 1S0 |
| Atomic Volume | cm3 mol-1 |
| Electronegativity | No data. |
| Magnetic ordering | No data |
| Mass magnetic susceptibility | -5.9 x 10-9 |
| Molar magnetic susceptibility | -2.36 x 10+-11 |
Thermal Properties |
|
| Enthalpy of Atomization | No data. |
| 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 | No data. |
| Critcal Temperature | 5.19 K (-267.96°C) |
| Critcal Pressure | No data. |
| Adiabatic index | No data. |
Electrical Properties |
|
| Electrical resistivity | No data. |
| Electrical conductivity | ? 106/cm Ω |
Chemical Properties |
|
| Ionization Potential | |
| 24.587 | |
| 54.416 | |
Flammability |
|
Optical Properties |
|
| Refractive Index (gas) | 1.000035 |
| Refractive Index (liquid) | 1.028 |
Energy Levels |
|
| 0.022 KeV | |
Atomic Radii |
|
| 31 pm | |
| 31 pm | |
| 32 pm | |
| 140 pm | |
| No data. | |
| No data. | |
Ionisation Energies (kJ mol-1) ![]() |
|
| 2372.3 | |
| 5250.4 | |
Vapour Pressure |
||||||
| P (Pa) | 1 | 10 | 100 | 1K | 10K | 100K |
| T (K) | 3 | 4 | ||||