# Why Use Lewis Structures to Determine Radicals

As far as I know, Lewis Structures are convenient for representing molecules, but give no insight on the actual electron orbitals.

For example: The Lewis Structure of $\ce{O_2}$ does not reflect paramagnetism. Therefore, we use MO theory to explain it.

Then, why are Lewis Structures used to show if a molecule is a radical?

For example: hydroxyl is drawn as $\ce{.OH}$ to reflect the unpaired electron. That is a Lewis Structure.

Why do Lewis Structures work in this case?

• Look at the history of atomic models. – Another.Chemist May 4 '16 at 5:19