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Oxygen (O)
Atomic number: 8 · Category: diatomic nonmetal · Group 16 · Period 2 · Phase: Gas
Oxygen 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.
Block: p
CPK color:#ff0d0d
Electronic structure
Electron configuration: 1s2 2s2 2p4
Configuration (semantic): [He] 2s2 2p4
Shells: 2, 6
Electronegativity (Pauling): 3.44
Electron affinity: 140.976
Ionization energies: 1313.9, 3388.3, 5300.5, 7469.2, 10989.5, 13326.5, 71330, 84078
Periodic position
Group: 16
Period: 2
xpos: 16
ypos: 2
Spectral/Bohr images
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3D Model