Conformational isomerism refers to the different spatial arrangements of atoms in a molecule that can occur due to rotation around single bonds. These arrangements, known as conformers or rotamers, can have distinct shapes and properties, even though they share the same molecular formula. The most common example of conformational isomerism is seen in alkanes, such as butane, which can exist in various forms like the staggered and eclipsed conformations. The energy differences between these conformers can influence the stability and reactivity of the molecule, making conformational isomerism an important concept in organic chemistry.