Question

How are structural isomers drawn?

Answer 1

Through many hours of hard practice!

Explanation:

Structural isomers have the same molecular formula, but different constitutions (e.g. connectivity of atoms).

Consider,

`C_4H_8O` with one degree of unsaturation.

It can have a double bond or a cyclic connection among the carbons (or oxygen, for that matter). I'll draw a few, but there are many constitutional isomers, on average,

That took me five minutes, and I'm sure there are more I missed (like a carbonyl `C=O` bond among a few of those alkanes).