Balancing N2 + O2?

Question

Why does N2 + O2 -> 2NO

The valence for N is 3+ and O is +2 so shouldn't it be

N2O3 ?

Answer 1

Excellent question!

There is in fact an oxide N2O3, as you predict, but it is rather unstable and decomposes into NO andNO2.

In fact, there are a whole load of different oxides of nitrogen. Those you meet most often, NO and NO2, cannot really be explained by simple models of bonding, or by reference to the usual valencies.