(i) Propose two resonance forms (that respect the octet rule and energetically nonequivalent) contributing to the structures for each of the following molecule and ion.
(ii) Show formal charges where they exist.
(iii) Circle the most stable
(a) H2CNN
(b) H2CNO2-
(c) ONCCH3
(d) CH2CO2H-
(e) C3H5O-
(f) C3H4O