Chemistry Resonance Question?

Question

I am a bit confused, and the only one I am pretty sure has resonance is CNS-.

Which of the following compounds/ions exhibit resonance? Select "yes" or "no" for each compound.

 yes no  SeO₂

 yes no  N₃^-

 yes no  OCl₂

 yes no  CNS^-

 yes no  NF₃

 yes no  SeS₃

Answer 1

Draw the Lewis dot structures (difficult to do on this site without using the video option). I will do a few so you get the idea.

SeO₂. Lewis dot would be something like this. O=Se-O with 1 lone pair on the Se, 2 lone pairs on the double bonded O and 3 lone pairs on the single bonded O. This will show resonance because you can switch the double bond to the other O atom.

N₃^-. There are a total of 16 valence electrons so the Lewis dot would look like this. N = N = N with no lone pairs on the central N atom, and 2 lone pairs on each of the other N atoms. This would not show resonance.