Question

Total 4 and Bonded 2 give you a molecular geometry of?

A) Bent, 109.5°
B) Trigonal Planar, 120°
C) Tetrahedral, 109.5°
D) Trigonal Bipyramidal, 120° and 90°

Answer 1

A molecule with a total of 4 regions of electron density and 2 bonded atoms has a bent molecular geometry with a bond angle slightly less than 109.5°, typically around 104.5° as in water (H2O).

Step-by-step explanation:

When a molecule has a total of 4 regions of electron density (electron pairs, both bonding and nonbonding) and 2 of those are bonded atoms, the remaining two must be nonbonding electron pairs, also commonly known as lone pairs. According to VSEPR theory, such a scenario gives us a tetrahedral electron-pair geometry. However, because the molecular geometry is determined only by the positions of the nuclei (bonded atoms), the presence of the lone pairs will alter the shape, pushing the bonded pairs closer together. This results in a bent or V-shaped molecular geometry with a bond angle slightly less than 109.5°. Specifically, the molecule will have a bent molecular geometry with a bond angle of about 104.5°, as in the case of water (H2O).