8O
Oxygen
산소 · 酸素
Nonmetal
Atomic number8
ElementO — Oxygen
Atomic mass15.999
CategoryNonmetal
Group16
Period2
Electron config[He] 2s2 2p4
Shells2,6
State (RT)Gas
Melting pt-218°C
Boiling pt-183°C
Electronegativity3.44
Discovered1774
Main usesRespiration, steelmaking, welding
2 · 6