Question

what is the valency of nitrogen in nitrogen dioxide

Answer 1

Nitrogen - Z=7
valence electrons 5
valency -3
oxygen-Z=8
valence electrons 6
valency 2
but in case of NO2:
two oxygen atoms require 4. electrons for stability.
so they share 3 nitrogen electrons and one among themselves.
but in case of nitrogen in NO2 its valency is not satisfied. hence it exists as dimer N2O4.
structure: attached.
so valency 0f nitrogen is 4.

Answer 2

4 is the answer of this question.