Question

What is the Lewis structure for resonance form of `ClO_2^-`?

Answer 1

Well we has got................

`7_"Cl"+2xx6_"O"+1_"negative charge"=20*"valence electrons"` to distribute across 3 centres...

Explanation:

And so....we gots `"chlorite ion"`, which distributes 10 electron pairs as required....(there are 2 lone pairs on the doubly bound oxygen....and of course the negative charge is delocalized....

en.wikipedia.org

The electronic geometry around chlorine is tetrahedral. The molecular geometry is bent with `/_O-Cl-O~=109.5^@` to a first approx.