OpenStax
Open Stax: Catherine Schmidt Jones: Half Steps and Whole Steps
Take a look at the two intervals of the half step and whole step and how they make up the chromatic and whole tone scales. This page includes a couple of self checking problems to test your knowledge.
OpenStax
Open Stax: Catherine Schmidt Jones: Scales That Aren't Major or Minor
As the title suggests, this site defines and gives examples of various other types of scales including chromatic, whole tone, blues scales and more.