What is the term for molecules that have the same molecular formula but different structures?

The term that describes molecules sharing the same molecular formula but differing in their structural arrangement is isomerism. Isomers can have varied properties despite having the same number of each type of atom. This structural diversity can result in molecules that behave differently in chemical reactions, have different physical properties, or exhibit different biological activities.

Isomerism encompasses various types, including structural isomers, where the connectivity of atoms differs, and stereoisomers, where the spatial arrangement of atoms differs, impacting how the molecules interact with other substances. Examples include but are not limited to positional isomers, functional group isomers, and geometric isomers.

The other terms listed refer to different concepts within chemistry. Homology typically relates to a series of compounds that differ by a repeating unit, polymerization involves the process of forming polymers from monomers, and enantiomerism concerns molecules that are non-superimposable mirror images of one another. These terms do not convey the structural arrangement distinction found in isomers, highlighting why isomerism is the correct choice in this context.