9. Major Scale ➜ The 7 Diatonic Chords ➜ Key

C Major Scale

These are the seven notes in the C major scale, displayed below on a piano keyboard.

Major Scale ➜ 7 Diatonic Chords

Each of these seven notes serves as a root note for a diatonic chord.

Building Chords in the C Major Scale

The 1 Chord – C Major

A major chord consists of three notes: the root note, a major third, and a fifth.

• The root note is C.
• The major third is E (4 semitones from C).
• The fifth is G (7 semitones from C).

The 2 Chord – D Minor

A minor chord consists of three notes: the root note, a minor third, and a fifth.

• The root note is D.
• The minor third is F (3 semitones from D).
• The fifth is A (7 semitones from D).

The 3 Chord – E Minor

• The root note is E.
• The minor third is G (3 semitones from E).
• The fifth is B (7 semitones from E).

The 4 Chord – F Major

• The root note is F.
• The major third is A (4 semitones from F).
• The fifth is C (7 semitones from F).

The 5 Chord – G Major

• The root note is G.
• The major third is B (4 semitones from G).
• The fifth is D (7 semitones from G).

The 6 Chord – A Minor

• The root note is A.
• The minor third is C (3 semitones from A).
• The fifth is E (7 semitones from A).

The 7 Chord – B Diminished

A diminished chord consists of three notes: the root note, a minor third, and a diminished fifth.

• The root note is B.
• The minor third is D (3 semitones from B).
• The diminished fifth is F (6 semitones from B).

The 7 Diatonic Chords on the Circle of Fifths

The seven diatonic chords of the C major scale are labeled on the Circle of Fifths below.

The Concept of Key in Music

The lesson I want to convey is that the 7 notes in the C major scale serve as the root notes for 7 diatonic chords. Together, these 7 notes and their corresponding 7 diatonic chords form the key of C major.

Every song is composed in at least one key. A key is a tonal home base, determining the notes and chords used in a song. Sometimes, songs change keys during progression to:

• Shift the mood (happiness or sadness)
• Create contrast and keep the listener engaged
• Highlight different sections of the song
• Tell a musical story (e.g., from despair to hope)

Later in this course, I will teach you how to transition between keys effectively.

Summary

• The major scale consists of seven notes.
• Each of these seven notes serves as a root note for a diatonic chord.
• A major chord is built with a root note, a major third, and a fifth.
• A minor chord is built with a root note, a minor third, and a fifth.
• A diminished chord is built with a root note, a minor third, and a diminished fifth.
• The seven diatonic chords of the C major scale are: C Major (1), D Minor (2), E Minor (3), F Major (4), G Major (5), A Minor (6), and B Diminished (7).
• The 7 notes in the C major scale and their 7 diatonic chords form the key of C major.
• Every song is composed in at least one key, which determines the notes and chords used.
• Songs can change keys to shift mood, create contrast, highlight sections, or tell a musical story.

Goal Achieved

You have successfully learned about the seven notes in the C major scale and how they correspond to the seven diatonic chords, establishing a foundational understanding of the key of C major.

What's Next?

Ready to put your knowledge of the C Major Scale into practice on the guitar? Next chapter, you'll learn to play all seven diatonic chords on the E string by mastering just three essential chord shapes: one for major, one for minor, and one for diminished. You'll then apply these chords to play sections of well-known songs and explore the unique emotional character of each chord to begin crafting your own four-chord progressions.