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

To determine the molecular geometry of a molecule with 6 electron domains and 5 bonding pairs, we need to understand how electron domains (which can include bonding pairs and lone pairs) arrange themselves in space to minimize repulsion, according to the VSEPR (Valence Shell Electron Pair Repulsion) theory.

In this scenario, having 6 electron domains suggests that the basic geometric arrangement starts with an octahedral shape, which is characterized by 90-degree bond angles. In the presence of 6 total electron domains:

- 5 of these are bonding pairs, which form bonds with other atoms.

- 1 must be a lone pair (non-bonding).

When applying the VSEPR theory to an octahedral arrangement with one lone pair, the lone pair will occupy one vertex of the octahedron. The remaining bonding pairs will then adjust accordingly, leading to a geometry that is derived by removing one vertex from the octahedral shape.

This results in a square pyramidal geometry. In summary, with 6 electron domains and 5 of those dedicated to bonding, the arrangements lead to a square pyramidal shape, confirming that the correct answer is indeed square pyramidal.