According to the VSEPR theory, the geometry of the SO3 molecule isa. pyramidal b. tetrahedral c. trigonal planar d. distorted tetrahedron (see-saw). e. square planar
The Correct Answer and Explanation is:
The correct answer is c. trigonal planar.
Here’s the explanation according to the VSEPR (Valence Shell Electron Pair Repulsion) theory:
- Molecular Formula and Electron Domains:
The sulfur trioxide molecule (SO₃) consists of one sulfur (S) atom centrally bonded to three oxygen (O) atoms. Each S=O bond in SO₃ involves a double bond. Therefore, there are three bonding pairs of electrons and no lone pairs around the central sulfur atom. - Electron Domain Count:
The VSEPR theory predicts that electron pairs around a central atom will arrange themselves as far apart as possible to minimize electron pair repulsion. In SO₃, the sulfur atom has three bonding regions and no lone pairs. The three bonding pairs will arrange themselves in a way that maximizes their separation. - Molecular Geometry:
With three bonding pairs and no lone pairs, the geometry of the SO₃ molecule is trigonal planar. In this arrangement, the three oxygen atoms are positioned at 120° angles from each other, lying in the same plane around the central sulfur atom. - Bond Angles:
In a trigonal planar structure, all the bond angles between the atoms are 120°. The molecule is flat and symmetric, which is typical for molecules with a trigonal planar geometry. - No Lone Pairs:
The absence of lone pairs on the central sulfur atom helps maintain the ideal bond angles of 120° and the symmetrical trigonal planar shape.
Thus, according to VSEPR theory, the molecular geometry of SO₃ is trigonal planar.
