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.
Open Curriculum
Open Curriculum: Scales That Are Not Major or Minor
To explain the various musical scales that cannot be classified as major or minor such as chromatic, whole-tone, pentatonic, blues, and scales from non-Western music
Other
Music Theory First Aid for Struggling Students
This site provides music theory information on such topics as rhythm, intervals, scales, chords, etc. Also, there is a fine section which describes the basic concepts of form and structure.
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.
Music Theory
Music theory.net
An online beginning music theory and ear training site. This site is for students to use at home to reinforce what they learn in class.