Helium

Symbol | He
Latin name | Helium
Atomic number | 2
Period | 1
Element category | Noble gases
Relative atomic mass | 4.002602
Group | VIII.A
Oxidation numbers |
Electron configuration | 1s2
Density [g/cm3] | 0.0001785
State | Gas
Melting point [°C] | -272.12
Boiling point [°C] | -266.934
Critical point [°C] | -267.96
Critical pressure [MPa] | 0.227
Atomic radius [pm] | 31
Covalent radius [pm] | 32
Thermal conductivity [W m-1K-1] | 0.152
Heat capacity [J K-1g-1] | 5.193
Discovery | 1868
Stable isotopes | 2
Unstable isotopes | 2