Question

Rank the resonance structures in each row of the table from major to minor. For example, in the first row, select

1 (major) for the major resonance contributor. If two or more structures in the same row contribute equally, rank them equally by selecting the same number.

H-N-C=c-H H H–ï=c=č—H (Rank) (Rank) 1 (major) HH Η Η Ć-Ć H-O: H. C + H och :Br: :Br: (Rank) (Rank) v

Answer 1

Н—N—C—С—Н Н—N—C3C—Н Major Because the negative charge is on electronegative atom nitrogen Minor Because the negative charge is on less electronegative sp2 atom carbon. н н нн Н. Н. н н Br: Minor Because the positve charge is on electronegative atom Br. Br Major Because the positve charge is on less electronegative atom C. and stabilized via resonance effect of Br

н—ӧ: н н .о—н Н—о—с- с—н Н—0—с—с—н н These are equivalent structures hence they contribute equally. So select major major for both. н