Constitutional Isomers

“How are the following two molecules related to each other?”

Does this sound familiar? This is one of the most important questions you will have to answer in Organic Chemistry 1. 

Definition of Constitutional Isomers

Constitutional isomers are molecules with identical atoms but different connectivity

Constitutional Isomer Flowchart

Concept: Using the flowchart to determine isometric relationships.

6m

Problem: How are the following two compounds related? 

3m

Are they different molecules, constitutional isomers or identical? 

Problem: How are the following two compounds related? 

2m

Is there a choice we can rule out immediately? 

Problem: How are the following two compounds related? 

4m

So now you should have a pretty good idea of how to solve questions asking for molecular relationship.