Final answer:
Two molecules with identical formulas but different shapes are known as stereoisomers, and a subtype of these, where molecules are mirror images of each other, are called enantiomers.
Step-by-step explanation:
Two molecules with identical formulas but different shapes are called stereoisomers. When these molecules are nonsuperimposable mirror images of each other, they are referred to as enantiomers. The concept of isomerism, including structural isomers and geometric isomers, highlights the three-dimensional nature of molecules and explains how the same molecular formula can lead to molecules with different physical and chemical properties. Structural isomers differ in the covalent arrangement of their atoms, whereas geometric isomers have different spatial arrangements of atoms around a double bond.