Question

What is the oxidation state of an individual nitrogen atom in NH2OH?

Answer 1

Oxidation number is the charge left on the central atom when all the bonding electrons are removed with the charge going to the most electronegative atom.

Explanation:

Electronegativity is a formalism or a concept, it is a contrived parameter; formally it is the tendency of an atom in an element to polarize electron density towards itself. Electronegativity increases across a Period (because nuclear charge, `Z`, increases sequentially). Because oxygen has greater nuclear charge than nitrogen, it formally is more electronegative.

So if we split up hydroxylamine: `H_2N-OHrarr H_2N^+ + HO^-`.

Then split up the nitrogen containing fragment:

`H_2N^+ rarr 2H^+ +N^-`

So the oxidation state of nitrogen in hydroxylamine is `-I`. Remember that this is a formalism, that does not have real physical significance.

If I do the same for ammonia, or methane, I get `N(-III)`, and `C(-IV)`. What about nitric oxide, `NO_2`?

See this link for related discussion: http://socratic.org/questions/oxygen-has-1-oxidation-state-in-peroxide-but-each-oxygen-forms-two-bonds-why