How do I figure out thr number of electron groups in a molecule? I thought it was the number of atoms around the central atom but for some cases it isnt right.

For SnCl2, is it 2 electron groups.
For H2O2, how would I figure that out, since both oxygens are the central atoms, would it be two?

3 answers

You need to explain what you mean by electron groups. Are you talking about "regions of high electron density"?
I mean how many electron groups to determine the shape of it...VSEPR
Yes, you are talking about regions of high electron density.

2 linear
3 trigonal planar
4 tetrahedral
5 trigonal bipyramid
6 octahedral