Sulfur is the central atom:

There are 3×6 + 6 + 2 = 26 electrons, and 6 of them are used to make 3 bonds. Three oxygens take 3 lone pairs each and one goes to the sulfur:

All the electrons have been used; however, one oxygen needs to share a pair of electrons with the sulfur otherwise the ionic would be -3:

The central atom has 3 atoms and a lone pair and therefore, **the electron geometry is tetrahedral **while the** molecular geometry is trigonal pyramidal.**

Steric number 4 corresponds to *sp*^{3}-hybridization where the idealized bond angles are 109.5^{o}. Because the groups on the central atom are not identical, the bond angles differ from the idealized values.

**More practice examples on geometry and hybridization in this multiple-choice quiz:**

Free

### Geometry and Hybridization Quiz