Rationalization of bond angle/ bond pair repulsions.

1. The problem statement, all variables and given/known data

I need help rationalizing the following:

a) Bond angle for H₂S is only 92^o whereas bond angle for H₂O is 104.5^o.



b) If bond-pair<-> bond-pair repulsion is maximum for the C-H bonds in CH₃X, ∑ all bond angles is 450^o for CH₃X



c) For CH₂Br₂, the H-C-Br will be the smallest bond angle observed.



2. Relevant equations

main considerations:

a) magnitude of central atom non-bonding pairs<->single bonding pairs repulsion w/ bonding-pair <-> bonding pair.



b) I got nothing



c) Br- Br repulsion? Magnitude of Br





3. The attempt at a solution

see main considerations



I realize this is a lot. I appreciate any help/ guidance from someone with a firm grasp on this stuff.

Thanks in advance.