Explanation:
A molecule which contains three bond pairs but no lone pair of electrons will have a trigonal planar geometry.
Hybridization of such a geometry is [tex]sp^{2}[/tex].
For example, [tex]BF_{3}[/tex] is a trigonal planar molecule.
As, hybridization of [tex]BF_{3}[/tex] will be calculated as follows.
Hybridization = [tex]\frac{1}{2}[V+N-C+A][/tex]
where,
V = number of valence electrons present in central atom
N = number of monovalent atoms bonded to central atom
C = charge of cation
A = charge of anion
Hybridization = [tex]\frac{1}{2}[V+N-C+A][/tex]
= [tex]\frac{1}{2}[3 + 3][/tex]
= 3
So, the hybridization of [tex]BF_{3}[/tex] will be [tex]sp^{2}[/tex]. As there are 3 bond pairs and no lone pair of electrons. Hence, the geometry of [tex]BF_{3}[/tex] is trigonal planar.
Thus, we can conclude that according to the VSEPR theory, the shape of a molecule that has a central atom bound to three other atoms with no lone pairs of electrons is trigonal planar.
