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8O15.999
Oxygen
Diatomic NonmetalOxygen is a chemical element with symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table and is a highly reactive nonmetal and oxidizing agent that readily forms compounds (notably oxides) with most elements. By mass, oxygen is the third-most abundant element in the universe, after hydrogen and helium.
Phase: Gas
2, 6
Physical Properties
Atomic Mass15.999 u
Density1.429 g/cm³
Melting Point54.36 K
Boiling Point90.188 K
Period2
PhaseGas
Chemical Properties
Electron Configuration1s2 2s2 2p4
Semantic Config[He] 2s2 2p4
Shells2, 6
Electron Affinity140.976 kJ/mol
Electronegativity3.44
Ionization Energies
IE1: 1313.9 kJ/molIE2: 3388.3 kJ/molIE3: 5300.5 kJ/molIE4: 7469.2 kJ/molIE5: 10989.5 kJ/molIE6: 13326.5 kJ/molIE7: 71330 kJ/molIE8: 84078 kJ/mol
Discovery