Final answer:
Structural (constitutional) isomers have different arrangements of atoms, while stereo-isomers have the same arrangement of atoms but different spatial orientations.
Step-by-step explanation:
Structural (constitutional) isomers and stereo-isomers are two types of isomers that have different characteristics.
Structural isomers have different arrangements of atoms in their structures. This means they have the same molecular formula, but different structures. For example, butane and isobutane are structural isomers. Both have the molecular formula C4H10, but their structures are different. Butane has a straight chain of four carbon atoms, while isobutane has a branched structure with three carbon atoms and one methyl group attached.
Stereoisomers, on the other hand, have the same arrangement of atoms in their structures, but their spatial orientation is different. This means they have the same molecular formula and same structures, but different three-dimensional arrangements. For example, cis-2-butene and trans-2-butene are stereoisomers. Both have the molecular formula C4H8, and their structures have the same arrangement of atoms bonded together. However, the orientation of the methyl groups on the double bond differs in cis-2-butene and trans-2-butene.
In summary, structural isomers have different arrangements of atoms, while stereoisomers have the same arrangement of atoms but different spatial orientations.