Determine the number of electron groups around the central atom for each molecule of2 nf3 cs2 ch4

All of the 4 electron groups have sp3 hybrid orbitals, and tetrahedral orbital geometry.

CH4 has 4 bonded pairs. Tetrahedral molecular geometry

NF3 has 3 bonded pairs with 1 unshared pair. Pyramidal molecular geometry

OF2 has 2 bonded pairs with 2 unshared pairs. Bent molecular geometry

H2S has 2 bonded pairs with 2 unshared pairs. Bent molecular geometry