[de5truction]

my high school teacher stressed in a post-exam lecture that the bond between N and O can hardly be a dative because both are almost equally electronegative, so both are not willing to donate a pair of electron to the other.  is this the case?

[Donaldson Tan]

oxygen is more electronegative than nitrogen. On the pauling scale, nitrogen is measured as 3.04 whereas oxygen is measured as 3.44. The difference of 0.4 represents about 20% of that oxygen. I would not consider that as negligible difference.

The only reason why there is no dative bond between N and O is that the octet rule does not allow it to happen.