Structural isomerism refers to the phenomenon where compounds with the same molecular formula have different structural arrangements of atoms. This means that while the number and types of atoms are identical, their connectivity differs, leading to distinct chemical properties. For example, C4H10 can exist as butane and isobutane, which have different structures and behaviors. There are several types of structural isomerism, including chain isomerism, position isomerism, and functional group isomerism. Chain isomerism occurs when the carbon skeleton varies, while position isomerism involves the location of functional groups changing within the molecule. Functional group isomerism arises when different functional groups are present, despite having the same molecular formula.