Oxygen

Symbol | O
Latin name | Oxygenium
Atomic number | 8
Period | 2
Element category | Nonmetals
Relative atomic mass | 15.9994
Group | VI.A
Electronegativity | 3.5
Oxidation numbers | -2, -1, 2
Electron configuration | 1s2 2s2 2p4
Density [g/cm3] | 0.001429
State | Gas
Melting point [°C] | -218.79
Boiling point [°C] | -182.962
Critical point [°C] | -118.56
Critical pressure [MPa] | 5.043
Atomic radius [pm] | 48
Covalent radius [pm] | 73
Thermal conductivity [W m-1K-1] | 0.2674
Heat capacity [J K-1g-1] | 0.92
Discovery | 1774
1.st ionization energy [eV] | 13.6181
2.nd ionization energy [eV] | 35.117
3.rd ionization energy [eV] | 54.934
Stable isotopes | 3
Unstable isotopes | 5