Here's why:

* Central atom: Sulfur (S) is the central atom.

* Valence electrons: Sulfur has 6 valence electrons, and each oxygen (O) atom has 6 valence electrons.

* Bonding: Sulfur forms double bonds with each of the three oxygen atoms.

* Electron pairs: There are three bonding pairs and no lone pairs on the sulfur atom.

* Shape: According to VSEPR theory (Valence Shell Electron Pair Repulsion), the electron pairs will arrange themselves to minimize repulsion, leading to a trigonal planar geometry with bond angles of 120 degrees.