Hey & welcome to GT!

Originally Posted by: ccrider19632I’m in the process of trying to teach myself basic music theory. My question is with the major open scales. It looks to me that there are generally 5 major open scales.

A/C/D/E and G. Is this correct? What about B and F and if not, why?

Often beginners learn to play major scales based on the open strings. But most scales can & do use open strings. I encourage you to work through one of the Fundamentals courses in order to get the appropriate amount of theory along with practical physical playing skills at the same time.

I cover intervals, scales & basic theory starting here.

https://www.guitartricks.com/course.php?input=fundamentals2(discontinued)

To answer your question more directly, there are 12 possible musical alphabet notes: 7 letters A through G & the 5 accidentals (sharps & flats) between them. I cover that in this series of lessons.

https://www.guitartricks.com/lesson.php?input=11078&s_id=1138

You can build a scale on every one of them. So, there are 12 possible major scales. But this is way beyond what a beginner needs to know or practice! The best place to start is to learn one major scale & really work it out. Get used to playing it, hearing it, using it. That's where the courses are valuable.

Hope this helps. Please ask more if necessary & best of success!