Question

Distinguish between isomerism and resonance. Distinguish between structural and geometric isomerism.

Short answer

Resonance structures are representations of the same molecule, whereas isomers are separate molecules with the same molecular formula.

Geometric isomers only differ in the geometry of groups on a double bond, while structural isomers differ in connectivity only.

Step-by-step solution

Define the isomerism and resonance.

When two or more compounds have the same chemical formula but different chemical structures, this phenomenon is known as isomerism.

Resonance occurs when one object's oscillations are amplified by the corresponding vibrations of another object.

Step 2: Distinguish between the term isomerism and resonance.

When there are two or more potential valence-bond structures that differ only in electron distribution and only one of them may accurately represent a molecule's structure, the molecule will mostly be represented by both configurations. Resonance structures are the names given to these molecular configurations.

Compounds with the same molecular formula are isomers.

Stereoisomers and constitutional isomers can be used to categorize the isomers.

Step 3: Distinguish between structural and geometric isomerism.

Constitutional isomers share the same chemical structure but have distinct atom connections. Example; Structural isomers

$$\begin{gathered} {\text{CH}}_{\text{3}}{\text{- CH}}_{\text{2}}{\text{- CH}}_{\text{2}}\text{Br} \\ {\text{CH}}_{\text{3}}{\text{- CH(Br) - CH}}_3 \end{gathered}$$

Stereoisomers differ in their spatial orientation but share the same chemical structure and connection. Stereoisomers include geometric isomers or cis-trans isomers. The geometry of the groups on a double bond varies between them.