We have already seen how to find the triads that belong to the major harmonized scale.

..adding the 7th is very simple. If we stack another note a diatonic third apart from the last note we have found, we will have Seventh chords. As a matter of fact, the notes we have used to build the triad where the 1st, 3rd and 5th note of the major scale…the one we are adding is the 7th note of the scale. In C major it will give us the following 7th chords.

Cmaj7 Dm7  Em7    Fmaj7       G7      Am7   Bm7(b5)

Here you will find the most common 7th chords guitar shapes, just print out the file.

Printable file: Common 7th chords