Isomers
Isomers are compounds with the same molecular formula but different 
structures and properties.Prepared by Prof. Dr. Hilal Zaid 10/24/2024
22 Prepared by Prof. Dr. Hilal Zaid 10/24/2024
Structural Isomers:
Structural isomers differ in the connectivity of their atoms.o Example: Ethanol (C2H5OH) and dimethyl ether (C2H6O) have the 
same molecular formula but different functional groups (alcohol 
vs. ether).o Example: In but-2-ene, the cis isomer has the two methyl groups on 
the same side of the double bond, while the trans isomer has them on 
opposite sides.Types:
oChain Isomers: Variations in the carbon chain (e.g., straight-chain vs. 
branched).Stereoisomers
Stereoisomers have the same connectivity but differ in the spatial 
arrangement of atoms.