Why do chords tend to move in a particular order, and how do phrases end with cadences?
Topic 4.3 Harmonic Progression, Functional Harmony, and Cadences: explain tonic, predominant and dominant function, the normal direction of progressions, and the four cadence types.
A focused answer to AP Music Theory Topic 4.3, covering functional harmony (tonic, predominant, dominant), the normal flow tonic to predominant to dominant to tonic, and the four cadences (perfect authentic, imperfect authentic, half, plagal, with the deceptive cadence), with a worked cadence analysis.
Reviewed by: AI editorial process; not yet individually human-reviewed
Have a quick question? Jump to the Q&A page
Jump to a section
What this topic is asking
The College Board (Topic 4.3) wants you to explain functional harmony (the roles of tonic, predominant and dominant chords), the normal direction of a progression, and the four standard cadences (perfect authentic, imperfect authentic, half and plagal), plus the deceptive cadence.
Functional harmony
The functions form a one-directional cycle: tonic to predominant to dominant to tonic. The dominant almost never falls back to a predominant chord, because that would undo the tension it has just built. Recognizing function lets you predict and analyze progressions even before you name every chord.
Cadences
The PAC is the strongest and most conclusive, used to end important sections. The half cadence is open and inconclusive, often ending the first phrase of a pair. The deceptive cadence frustrates the expected resolution, extending a phrase.
Why functional harmony shapes music
The central idea is that tonal music works by a cycle of tension and resolution organized around the tonic. The dominant chord contains the leading tone, a half step below the tonic, and the chordal seventh of V7 adds a second tendency tone; together they generate the strongest pull in the system, which is why dominant to tonic feels like an arrival. Predominant chords prepare that dominant smoothly, and the tonic dissipates the tension. Cadences are simply where this cycle is made audible at the ends of phrases, and the strength of a cadence measures how complete the resolution is. Understanding function rather than memorizing chord lists lets you analyze unfamiliar music, predict what comes next in dictation, and write progressions that sound idiomatic, because you are working with the grammar of the style rather than guessing.
Identifying a cadence
To name a cadence, find the last two chords of the phrase, give each a Roman numeral, check the inversions, and look at the soprano on the final chord. Match the pattern: V to I in root position with the tonic on top is a PAC; ending on V is a half cadence; IV to I is plagal; V to vi is deceptive.
Try this
Q1. What is the normal functional order of a progression? [1 point]
- Cue. Tonic to predominant to dominant to tonic; the dominant does not normally return to a predominant.
Q2. How does a deceptive cadence differ from a perfect authentic cadence? [2 points]
- Cue. A PAC is V to I (strong arrival); a deceptive cadence is V to vi, where the expected tonic is replaced by the submediant, frustrating the resolution.
Exam-style practice questions
Practice questions written in the style of College Board exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
AP 2021 (style)1 marksSection I (multiple choice, written). A phrase ends V to I, both chords in root position, with the soprano on the tonic at the final chord. What cadence is this? (A) imperfect authentic (B) perfect authentic (C) half (D) plagalShow worked answer →
The correct answer is (B) perfect authentic.
A perfect authentic cadence (PAC) is V to I (or V7 to I) with both chords in root position and the soprano ending on scale degree 1 (the tonic). It is the strongest, most conclusive cadence.
(A) imperfect authentic (IAC) is also V to I but with a weakening factor, such as the soprano ending on degree 3 or 5, or a chord in inversion. (C) a half cadence ends on V, not I. (D) a plagal cadence is IV to I. The trap is calling any V to I a PAC; the PAC requires root position in both chords and the tonic in the soprano.
AP 2023 (style)2 marksSection II (free response, harmonic analysis). A phrase in F major ends with the bass moving B flat to F under the chords IV and I. Name the cadence and explain why it is weaker than an authentic cadence.Show worked answer →
A 2-point cadence-analysis question.
(1 point) The bass B flat to F under IV to I is a plagal cadence (subdominant to tonic), sometimes called the amen cadence.
(1 point) It is weaker than an authentic cadence because it lacks the leading tone of the dominant; without the half-step pull from degree 7 up to degree 1, the arrival on the tonic is gentler and less decisive than V to I.
Markers reward naming the plagal cadence (IV to I) and explaining the absence of the leading tone, which is what gives the authentic cadence its strong drive to the tonic.
Related dot points
- Topic 4.2 SATB Voice Leading: apply the rules of range, spacing, doubling, smooth motion and tendency-tone resolution when writing four-part harmony.
A focused answer to AP Music Theory Topic 4.2, covering the four-voice ranges, the spacing rule (no more than an octave between adjacent upper voices), doubling guidelines, the ban on parallels and voice crossing, and resolving the leading tone and tendency tones, with a worked voicing.
- Topic 4.1 Soprano-Bass Counterpoint: write and identify the four kinds of motion between the outer voices and avoid parallel perfect intervals.
A focused answer to AP Music Theory Topic 4.1, covering the four types of motion (parallel, similar, contrary, oblique) between the outer voices, the ban on parallel perfect fifths and octaves, the preference for contrary motion, and starting and ending intervals, with a worked example.
- Topic 5.1 Adding Predominant Function IV (iv) and ii (ii diminished): use the subdominant and supertonic chords to prepare the dominant and part-write them smoothly.
A focused answer to AP Music Theory Topic 5.1, covering predominant function, the IV (iv) and ii (ii diminished) chords, how they lead to the dominant, the use of ii6 and first-inversion predominants, and smooth part-writing, with a worked predominant progression.
- Topic 5.5 Cadences and Predominant Function: build complete cadential progressions with predominants and harmonise a given melody so it cadences correctly.
A focused answer to AP Music Theory Topic 5.5, covering full cadential progressions that include a predominant (such as I, IV or ii, V, I), how the predominant strengthens the approach to the cadence, and how to harmonise a given melody so the cadence lands correctly, with a worked harmonisation.
- Topic 3.5 Roman Numerals and SATB: label diatonic chords with Roman numerals showing root and quality, and arrange chord tones in the SATB four-voice texture.
A focused answer to AP Music Theory Topic 3.5, covering Roman numeral analysis (case shows quality, figures show inversion), the diatonic numerals of major and minor keys, the SATB four-voice layout and ranges, and how to spell a chord across four voices, with a worked analysis.
Sources & how we know this
- AP Music Theory Course and Exam Description — College Board (2024)