In NO3- ion, the number of bond pairs and lone pairs of electrons on nitrogen atom are

In N-atom, number of valence electrons = 5Due to the presence of one negative charge, number of valence electrons = 5 + I = 6 one O-atom forms two bond (= bond) and two O-atom shared with two electrons ofN-atomThus, 3 O-atoms shared with 8 electrons of N-atom.∴ Number of bond pairs (or shared pairs) = 4Number of lone pairs = 0