ACS Chemistry Practice Exam 2026 – The All-in-One Guide to Exam Success!

A molecule with five electron domains and three bonding pairs is characterized by a specific arrangement based on the principles of VSEPR (Valence Shell Electron Pair Repulsion) theory. In this scenario, the molecule has five regions of electron density, which can include both bonding pairs (the pairs of electrons shared between atoms) and lone pairs (non-bonding pairs of electrons).

When there are three bonding pairs and two lone pairs, the lone pairs occupy the equatorial positions in a trigonal bipyramidal electron geometry. This arrangement minimizes the repulsion among the electron pairs, as lone pairs are more repulsive than bonding pairs due to their localized nature. Consequently, the three bonding pairs will occupy the remaining positions, leading to a molecular structure that resembles a T-shape.

In summary, the T-shaped molecular geometry arises from the combination of three bonds and two lone pairs in a trigonal bipyramidal electron domain arrangement, confirming that this is indeed the correct description of the molecular geometry.