Major-key chord pattern
Every major key follows the same triad pattern:
In C major: C, Dm, Em, F, G, Am and Bdim.
Natural and harmonic minor
Natural minor gives:
In A minor: Am, Bdim, C, Dm, Em, F and G. Many songs change Em to E or E7 so G♯ strongly resolves to A; that dominant comes from harmonic minor.
The main harmonic functions
| Function | Common degrees | Effect |
|---|---|---|
| Tonic | I, vi / i, III | Rest and identity |
| Predominant | ii, IV / iv, VI | Movement away from home |
| Dominant | V, vii° | Tension pointing to tonic |
Progressions to hear
- C–G–Am–F (I–V–vi–IV): a clear pop cycle.
- Am–F–C–G (i–VI–III–VII): the same pitch collection with a minor centre when Am is emphasised.
- Dm–G–C (ii–V–I): a compact predominant–dominant–tonic cadence.
Check melody notes against the current chord
A note may belong to the key and still create tension over a particular chord. Over C major, E is stable; F behaves like a suspension; F♯ is chromatic. For long backing-vocal syllables, check the note against the chord, not only against the scale.
Why non-diatonic chords are not errors
Real songs use secondary dominants, modal mixture, borrowed chords and chromatic bass. D major in C major may act as V of G; F minor may be borrowed from C minor. The diatonic list is a starting point, not a ban on every other chord.
Questions and answers
Why is vii° diminished?
Stacking scale thirds above the seventh degree creates two minor thirds.
Why is E major common in A minor?
G♯ becomes a leading tone to A and creates a stronger cadence.
Can a melody note sit outside the chord?
Yes, as a passing, neighbour or suspension note.
Does this apply to seventh chords?
The degree logic remains, but the added third changes colour and quality.