What is the #"oxidation number"# of nitrogen in #"ammonia, ammonium ion, and nitrate ion"#?

1 Answer
Aug 2, 2017

Answer:

We gots #stackrel(-III)N#..........

Explanation:

While oxidation number is a formalism, it is a convenient formalism. For ions and molecules, the SUM of the oxidation numbers ALWAYS equals the charge on the ion.

TO illustrate, let's take #NH_3#, #NH_4^+#, and #NO_3^-#; now hydrogen and oxygen in their compounds typically take oxidation numbers of #+I# and #-II# respectively, and they do here.......

ANd thus for ammonia, #3xx(+I)+stackrel"oxidation number"N=0#. Clearly we gots #stackrel"-III"N#.

And for ammonium, #4xx(+I)+stackrel"oxidation number"N=+1#. Clearly we gots #stackrel"-III"N# again.

But for nitrate ion, oxygen is MORE electronegative than nitrogen, and it gets the electrons, #3xx(-II)+stackrel"oxidation number"N=-1#. Clearly we gots #stackrel"+V"N#.

Capisce?

What about #NO#, #NO_2#, #N_2O_5#, #N_2O_4#?