CN and ion bond strength?

Question

Can anyone give the order of bond strength of the following?

a) CN+

b) CN

c) CN-

Answer 1

a) total valence electrons: 8
In bonding orbital: 8
In antibonding orbital: 0
bonding order: 4
b) total valence electrons: 9
In bonding orbital: 8
In antibonding orbital: 1
bonding order: 3.5
c) total valence electrons: 10
In bonding orbital: 8
In antibonding orbital: 2
bonding order: 3

Therefore: CN+ stronger than CN stronger than CN-

Answer 2

Draw a diagram of each, and refer to electronegativity values. Thus, HBr is polar, as the hydrogen attracts the positive charge, and the bromide ion attracts the negative charge, resulting in a dipole-dipole moment. N2, however, is not, as both sides of the molecule have equal electronegativities, resulting in no dipole-dipole moment (charge is not pulled one way or another). BCl3 is not polar either, as, although charge is pulled to the chlorine, the shape of the molecule is trigonal planar, so the effect of that is cancelled out. Use the same strategy for SO2 and SO3. There is not as great a dipole-dipole moment here (both are in the same group). But SO2 is more polar due to the shape of the molecule (it looks bent).