I came across a problem : ClO2 molecule, what is the hybridization of the central atom.
Here is what I did :
1) Central atom is chlorine since least electronegative
2) Counted total valence electrons : 7 + 2*6 = 19 e-
3) Draw skeleton lewis structure : 19-4 = 15e- left
4) Fill in octets for terminal atoms (oxygens), 15-12 = 3e- left
5) I am left with a lone pair and a single unpaired electron on the chlorine
6) Add two double bonds to chlorine atom, properly filling octet, chlorine is on third period so can have expanded octet (total 9e- including single unpaired e-)
here is my problem : chlorine has two atoms bonded to it, and one lone pair, it’s steric number is 2+1 = 3. Therefore it’s hybridization should be sp2.
However the answer in the problem set says it is sp3.
Does the single unpair electron count as a lone pair and get hybridized?