Triads
A triad is a three-note chord built by stacking two thirds above a root note. The four types differ in which thirds are used.
| Type | Sound | Example (C) |
|---|---|---|
| Major | Bright and happy | C – E – G |
| Minor | Dark and sad | C – E♭ – G |
| Diminished | Tense and unstable | C – E♭ – G♭ |
| Augmented | Unsettled, unresolved | C – E – G♯ |
Chords in a Key
Each note of a major scale can be used as the root of a triad built from notes within that key. These are numbered with Roman numerals. In C major:
| Numeral | Chord | Type | Name |
|---|---|---|---|
| I | C – E – G | Major | Tonic — home chord |
| II | D – F – A | Minor | Supertonic |
| III | E – G – B | Minor | Mediant |
| IV | F – A – C | Major | Subdominant |
| V | G – B – D | Major | Dominant — creates tension |
| VI | A – C – E | Minor | Submediant |
| VII | B – D – F | Diminished | Leading note |
Key fact: Chords I, IV, and V are the most important — they appear in almost all tonal music. The V chord creates tension that resolves back to I.
Cadences
A cadence is a chord progression at the end of a phrase that gives a sense of pause or ending. You must know all four for WJEC.
| Cadence | Chords | Feel |
|---|---|---|
| Perfect | V → I | Strong, finished — like a full stop |
| Imperfect | Any → V | Unfinished, questioning — like a comma |
| Plagal | IV → I | Gentle, "Amen" ending |
| Interrupted | V → any (not I) | Surprise — expected perfect, got something else |
Inversions
A chord is inverted when a note other than the root is in the bass. WJEC expects you to identify root position and first and second inversions.
| Position | Bass note | Symbol |
|---|---|---|
| Root position | Root | 5/3 or just the chord letter |
| First inversion | Third | 6/3 or letter + b |
| Second inversion | Fifth | 6/4 or letter + c |