To analyze the sulfur trioxide (SO3) molecule, we can start by identifying its electron geometry and molecular geometry, followed by its polarity.
Electron Geometry
The electron geometry is determined by the arrangement of electron pairs around the central atom. In SO3, sulfur (S) is the central atom surrounded by three oxygen (O) atoms. There are no lone pairs on the sulfur atom, and each of the three sulfur-oxygen bonds counts as one electron domain. Thus, there are three electron domains, which leads us to a trigonal planar electron geometry according to VSEPR (Valence Shell Electron Pair Repulsion) theory.
Molecular Geometry
The molecular geometry takes into account the arrangement of the atoms in the molecule. Since SO3 has no lone pairs on the sulfur and is symmetric with three identical oxygen atoms, the molecular geometry is also trigonal planar. This means that the three oxygen atoms are arranged in a flat plane around the sulfur atom.
Polarity
To determine the polarity of SO3, we need to look at the symmetry of the molecule and the electronegativity of the atoms involved. Oxygen is more electronegative than sulfur, which causes the bonds to be polar. However, due to the symmetric trigonal planar shape of SO3, the individual bond dipoles cancel each other out. As a result, SO3 is a nonpolar molecule overall.
In conclusion, SO3 exhibits a trigonal planar electron geometry, a trigonal planar molecular geometry, and is nonpolar due to the cancellation of dipoles.