He
Helium
Element 2 · Noble gas · Period 1, Group 18
Gas · Discovered 1868
Atomic Properties
| Atomic Number | 2 |
| Atomic Mass | 4.0026u |
| Electron Configuration | 1s2 |
| Atomic Radius | 140pm |
| Ionization Energy | 24.587eV |
| Oxidation States | 0 |
Physical Properties
| Standard State | Gas |
| Melting Point | 0.95K |
| Boiling Point | 4.22K |
| Density | 0.0001785g/cm³ |
| Group Block | Noble gas |
| Year Discovered | 1868 |