why is NO equal to nitrogen oxide

isn't the charge of N ion +3?

4 answers

Nitrogen is a multivalent compound,in this case, it is +2.
what does multivalent mean
http://www.memidex.com/multivalent+chemistry
Nitrogen has COMMON oxidation states of -3, 0, +1, +2, +3, +4, +5
examples:
-3 in NH3
0 in N2
+1 in N2O (laughing gas)
+2 in NO
+3 in N2O3
+4 in NO2
+5 in N2O5 and HNO3