National League for Nursing (NLN PAX) Practice Exam

What do you call compounds with the same atoms but different spatial arrangements?

1. Functional isomers.

2. Structural isomers.

3. Stereoisomers.

4. Geometric isomers.

The correct answer is: Structural isomers.

The correct answer refers to compounds that contain the same types and numbers of atoms but differ in the arrangement of these atoms in space. Stereoisomers are specifically types of isomers where the connectivity of the atoms is the same, but the spatial orientation differs. This category includes geometric isomers, which refer to specific types of stereoisomers that have different arrangements due to restricted rotation around a bond, typically seen in alkenes. In the context of isomerism, structural isomers refer to compounds that have the same molecular formula but differ in the connectivity of the atoms, meaning they are arranged in completely different ways at the structural level. However, the question specifically asks about spatial arrangements, which is a key element in defining stereoisomers. Therefore, it is the concept of stereoisomerism that best fits the description of compounds having the same atoms yet arranged differently in three-dimensional space. This distinction crucially involves understanding how atoms are oriented relative to one another in a molecule.