I just came across a YoutTube channel with instructional videos that look promising. I've only watched three so far, but from what I can tell, those three short lessons already have provided me with eye-opening insights to long-standing questions that no teacher ever told me.
I'm actually surprised these videos haven't accumulated more views.
Here is the first lesson in a series of ten that teaches going up the neck:
https://www.youtube.com/watch?v=cbAkddz8J1c
In this lesson, the teacher explains that a key not only consists of 7 notes, but 7 chords as well. I
think I get the concept behind it (harmonizing scales, correct?), but there is something that I'm confused about, and he doesn't explain it.
For the key of G, he says there are the following chords: G major, A minor, B minor, C major, D major, E minor and F major. I think I understand how these chords come to be -- we use only notes from the G scale to build them, and that's why some are major and some are minor -- but what I don't understand is why the seventh chord in the scale is flatted. There is no F in the G scale, so the resulting chord should be F# major, not F major. But the instructor makes it a point that it's flatted.
But why? Why does this one chord get an exemption from the rule of using only notes in the G scale?