Draw resonance structures for each of the following molecules or ions.

Question

OCN- (negative N-) Draw all the molecules by placing atoms on the grid and connecting them with bonds. Include all hydrogen atoms and all lone pairs of electrons. Show the charge of the ion over the central atoms ( C ).

Answer 1

O has 6 valence electrons

C has 4 valence electrons

N has 5 valence electrons

negative 1 = 1 valence electrons

Total = 16 valence electrons

Place C in the center and attach the O and the N with single bonds. Place 3 lone pairs of electrons around both the O and the N atom. This uses all 16 valence electrons, however C does not have an octet. Take 2 lone pairs from the N and make a triple bond between C and N. Now all atoms have an octet. In your question you say (negative N-). If by that you mean you want N to have a formal charge of 1-, then draw it as [O = C = N]^- with 2 lone pairs of electrons around both the N and O atom. This IS NOT the most stable form of OCN^- however. The more stable structure is [O = C ≡ N]^- . Both would represent resonance structures however, which is what the question asked for. You could also draw [O ≡ C - N]^- with 3 lone pairs on the N and 1 lone pair on the O.