Chords and Harmony - TCE Music (Tasmania)
“Construct triads and seventh chords, label them with Roman numerals and chord symbols, recognise inversions, and analyse progressions and cadences.”
A triad stacks two thirds: major (major third plus minor third), minor (minor third plus major third), diminished (two minor thirds) and augmented (two major thirds). Sevenths add another third on top. We label chords by Roman numeral relative to the key, or by chord symbols such as C, Dm and G7, and we describe inversions by which chord tone is in the bass. Progressions move between functions, and cadences are the punctuation that ends phrases.
What this dot point is asking
Building triads
A triad is three notes a third apart: a root, a third and a fifth. The quality depends on the two thirds. A major triad is a major third then a minor third (C E G). A minor triad is a minor third then a major third (C E flat G). A diminished triad is two minor thirds (C E flat G flat). An augmented triad is two major thirds (C E G sharp).
In any major key the triads built on each scale degree have a fixed pattern of qualities: I, IV and V are major, ii, iii and vi are minor, and vii is diminished. Knowing this pattern lets you harmonise a melody quickly without rebuilding every chord from scratch.
The root names the chord and sits at the bottom when the chord is in root position. The third decides whether the chord is major or minor. The fifth gives the chord stability. Adding a seventh above the root creates a seventh chord with extra colour and tension.
Seventh chords
Adding a third above the fifth makes a seventh chord. The dominant seventh (V7) is the most important: a major triad with a minor seventh, for example G B D F in C major. It contains a tritone between the third and seventh that resolves inward to the tonic, which is why V7 to I is such a strong progression. Other sevenths include the major seventh (bright, jazzy) and the minor seventh (smooth, common in pop and jazz).
Labelling: Roman numerals and chord symbols
There are two labelling systems. Roman numerals show a chord's function within a key: upper case for major (I, IV, V), lower case for minor (ii, vi), and a small circle for diminished (vii). This is the language of analysis because it shows the harmonic role regardless of key.
Chord symbols name the actual chord: C, Dm, G7, Fmaj7. These appear in lead sheets and popular music. You should be fluent in both, because the exam may give you one and ask for the other.
Inversions
A chord is in root position when its root is the lowest note. It is in first inversion when the third is lowest, and second inversion when the fifth is lowest. Figured bass shows inversions with numbers: 6 for first inversion, 6/4 for second inversion of a triad, and 7, 6/5, 4/3, 4/2 for the inversions of a seventh chord. In Roman-numeral analysis you write Ib or V6/5. Inversions smooth the bass line and create different colours from the same chord.
The dominant chord (V) contains the leading note, which pulls up a semitone to the tonic. In V7 the added seventh also pulls down to the third of I. These two voice-leading tensions resolving at once give the perfect cadence its sense of arrival.
Progressions and cadences
Harmony moves between functions: tonic (I, stable home), subdominant (IV, departure) and dominant (V, tension that wants to resolve). A cadence is the chord pair that ends a phrase. The perfect (authentic) cadence is V to I and sounds finished. The plagal cadence is IV to I, the "amen" sound. The imperfect (half) cadence ends on V and sounds unfinished, needing continuation. The interrupted (deceptive) cadence goes V to vi, surprising the ear by avoiding the expected tonic.
Step 1: Number each chord by its root
Given C, F, G, C in C major, find each root's scale degree. C is the first degree (tonic), F the fourth, G the fifth, and the final C the first again.
Step 2: Assign Roman numerals
Translate the degrees: C is I, F is IV, G is V, and the final C is I. The progression is I IV V I.
Step 3: Name the cadence and function
The last two chords are V to I, a perfect cadence that resolves home. The IV provides a subdominant departure before the dominant tension of V resolves to the tonic, giving the progression its sense of closure.
Hearing harmony
Aural harmony tasks ask you to identify chord qualities, simple progressions and cadence types. Listen first to the bass line, which often outlines the roots. Then judge whether each chord sounds major or minor, and whether the phrase ends with a sense of completion (perfect or plagal) or suspension (imperfect or interrupted). Singing the bass and the roots aloud trains this skill faster than passive listening.
A chord can be minor in quality but still act as a predominant or tonic-substitute in function. Do not assume every minor chord is "sad" or unimportant. In analysis, name the quality (minor) and the function (for example ii or vi) separately, because the exam rewards both.
Exam-style questions
Questions in the style of TASC exam questions on this dot point, each with a worked answer. They are written by ExamExplained unless tagged "Past paper"; the year shows the paper a question is modelled on.
Practice8 marksFor the four-chord progression C, Am, F, G7 in C major, label each chord with a Roman numeral, identify any inversion implied if the bass moves C, A, F, B, and name the cadence type formed by the last two chords.Show worked answer →
Label by scale degree in C major: C is the tonic, so I. Am is built on the sixth degree and is minor, so vi. F is built on the fourth degree, so IV. G7 is the dominant seventh, so V7.
If the bass for G7 is B (the third of the chord) rather than G, it is in first inversion, written V6/5 in figured-bass terms; otherwise it is root position V7.
Cadence: the last two chords are IV to V7, which ends on the dominant and sounds unfinished, so it is an imperfect (half) cadence, not a perfect cadence. For full marks, distinguish quality (minor vi) from function and name the cadence by the final two chords, not just the last one.
Practice6 marksExplain why the dominant seventh chord resolves so strongly to the tonic, referring to specific chord tones, and describe how an interrupted cadence subverts that expectation.Show worked answer →
The dominant seventh (V7) contains a tritone between its third (the leading note) and its seventh. In C major, G7 is G, B, D, F: the B (leading note) pulls up a semitone to C, and the F (seventh) pulls down a semitone to E. Both tensions resolve at once into the tonic chord, which is why V7 to I sounds so final.
An interrupted (deceptive) cadence sets up that expectation with V (or V7) but then moves to vi instead of I. In C major that is G7 to Am. The leading note still rises to C, but the bass moves to A, so the ear is surprised, the phrase feels suspended, and the music is pushed onward rather than closed. Marks come from naming the specific resolving tones and contrasting V to I with V to vi.