What is the oxidation number for oxygen?

1 Answer
Mar 5, 2014

In its compounds, Oxygen usually has an oxidation number of -2 , #O^-2#

Oxygen has an electron configuration of

#1s^2 2s^2 2p^4#

To complete its valence shell and satisfy the octet rule, the oxygen atom will take on two electrons and become #O^-2#.

In peroxides, such as #"H"_2"O"_2#, #"Na"_2"O"_2#, and #"BaO"_2"#, each oxygen atom has an oxidation number of -1.

In the free element, #"O"_2"#, each oxygen atom has an oxidation number of zero.

I hope this was helpful.

SMARTERTEACHER