Review AP Music Theory Unit 7 to understand how secondary dominant and secondary leading-tone chords create tonicization, temporarily making non-tonic chords sound like home without changing the primary key. This unit also covers the part-writing rules that govern how these chromatic chords resolve in four-voice SATB texture.
Use the topic guides, key terms, and practice questions available for this unit to work through Roman numeral analysis, spelling, and part-writing tasks.
Tonicization is one of the most common sources of chromaticism in common-practice tonal music. When a composer wants a chord other than the tonic to feel like a momentary goal, they place that chord's own dominant or leading-tone chord immediately before it. The result is a brief dominant-to-tonic pull aimed at a non-tonic chord, all without leaving the primary key.
Tonicization is a local harmonic event. It creates a fleeting sense of a temporary tonic but does not establish a new key because there is no cadence in that key. It differs from modulation, which involves a confirmed key change. The primary key remains in effect throughout.
A secondary dominant is a major triad or dominant seventh chord built on the fifth scale degree of a target chord. For example, V/V in C major is D-F#-A, because D is the fifth of G. The accidental (F#) is the chromatic alteration that signals tonicization. Any major or minor triad in the key can be tonicized this way.
A secondary leading-tone chord is a diminished triad (first inversion only, vii°6) or a diminished seventh chord (fully diminished vii°7 or half-diminished viiø7) built on the leading tone of the target chord. For example, vii°7/V in C major is built on F# and resolves to G major. These chords use the same resolution tendencies as diatonic leading-tone chords.
Both secondary dominants and secondary leading-tone chords work because they import the strongest harmonic motion in tonal music, dominant-to-tonic resolution, and aim it at a chord other than the home tonic. Understanding this shared logic makes it easier to spell, analyze, and part-write any applied chord: find the target, build its dominant or leading-tone chord, apply the necessary accidentals, and resolve according to standard voice-leading rules.
Defines tonicization as a local harmonic event and introduces secondary dominant chords (V/V, V/ii, V7/IV, etc.) as the primary means of achieving it. Covers Roman numeral slash notation, chromatic accidental spelling, and the distinction between tonicization and modulation.
Applies 18th-century voice-leading rules to secondary dominants: resolving the chordal seventh down by step, resolving the chromatic leading tone up by step, avoiding doubling the leading tone, and recognizing raised scale-degree patterns in soprano-bass counterpoint.
Introduces diminished triads (vii°6) and diminished seventh chords (vii°7 and viiø7) as applied leading-tone chords. Covers spelling, inversion rules, slash notation, and the difference between fully and half-diminished applied chords.
Extends leading-tone chord voice-leading rules to applied contexts: temporary leading-tone resolution, chordal seventh resolution, doubling restrictions, and avoiding parallel fifths and octaves. Includes score analysis and error detection tasks.
This snapshot uses Fiveable practice activity to show where students tend to miss questions and which review moves are worth prioritizing first.
Across 106 multiple-choice practice attempts for this unit.
Practice activity included in this snapshot.
Tonicization temporarily makes a non-tonic chord sound like a local tonic by preceding it with its own dominant. The effect is brief and lacks a cadence in the new key, so the primary key never changes. Secondary dominants are spelled by finding the fifth of the target chord and building a major triad or dominant seventh chord on that pitch, adding whatever accidental is needed.
| Feature | Tonicization | Modulation |
|---|---|---|
| Duration | Brief, one or a few chords | Extended, new key established |
| Cadence in new key | No | Yes |
| Primary key changes | No | Yes |
| Accidentals present | Yes | Yes |
| Roman numeral label | Applied chord (V/x) | New key Roman numerals |
When you part-write a secondary dominant, treat it exactly like a regular dominant chord aimed at a temporary tonic. The chromatic leading tone resolves up by step to the root of the target chord, and any chordal seventh resolves down by step. Avoid doubling the chromatic leading tone. In soprano-bass counterpoint, a raised scale degree moving up by step (such as raised 4 moving to 5) is a common signal that a secondary dominant is implied.
Secondary leading-tone chords tonicize a target chord by acting as its own leading-tone chord. They are built on the pitch a half step below the root of the target chord and come in three forms: diminished triad (first inversion only), fully diminished seventh, and half-diminished seventh. The half-diminished form (viiø7) appears only in major-mode contexts because it naturally occurs on the leading tone of a major key.
| Chord type | Structure | Inversion options | Example (target = V in C major) |
|---|---|---|---|
| vii°6 | Diminished triad | First inversion only | F#-A-C in first inversion |
| vii°7 | Fully diminished seventh | Any inversion | F#-A-C-Eb |
| viiø7 | Half-diminished seventh | Any inversion | F#-A-C-E (major-key context) |
Part-writing secondary leading-tone chords follows the same rules as part-writing diatonic leading-tone chords. The temporary leading tone resolves up by half step to the root of the target chord, the chordal seventh resolves down by step, and you must avoid doubling any tendency tone. Watch carefully for parallel fifths and octaves when the diminished seventh resolves, since all four voices move simultaneously.
Try AP-style multiple-choice questions and written prompts after you review the notes.
| Term | Definition |
|---|---|
| Secondary Dominants | Major triads or dominant seventh chords built on the fifth of a target chord, used to tonicize any major or minor triad in the key. Notated with a slash, such as V/V or V7/ii. |
| V/V | The secondary dominant of the dominant chord. In C major, V/V is D-F#-A; the F# is the chromatic alteration that creates a dominant pull toward G (V). |
| V/ii | A secondary dominant chord that tonicizes the ii chord of the primary key by acting as ii's own dominant, requiring a chromatic accidental to raise the temporary leading tone. |
| Dominant Function | The harmonic tendency of a dominant or leading-tone chord to resolve to a tonic. Secondary function chords borrow this tendency and aim it at a non-tonic chord. |
| Leading Tone Resolution | The tendency of a leading tone to resolve upward by half step to the tonic. In applied chords, the chromatic pitch acting as the temporary leading tone must resolve up to the root of the tonicized chord. |
| Chordal Seventh | The note a seventh above the root of a chord. In any secondary dominant or secondary leading-tone seventh chord, the chordal seventh must resolve down by step to the third of the target chord. |
| Roman numeral analysis | The system used to label chords by their scale-degree function. Applied chords use slash notation (e.g., vii°7/V) where the left side names the applied chord type and the right side names the target. |
| Modulation | A confirmed change of primary key, distinguished from tonicization by the presence of a cadence in the new key. Tonicization does not constitute modulation. |
| Harmonic Progressions | Sequences of chords that create movement and direction. Applied chords enrich progressions by introducing chromatic dominant-to-tonic motion aimed at non-tonic chords. |
| Stepwise Motion | Movement between adjacent scale degrees. The chordal seventh and temporary leading tone in applied chords both resolve by stepwise motion, down and up respectively. |
| Deceptive Resolution | A harmonic move in which an expected tonic resolution is replaced by a different chord. Secondary dominants can resolve deceptively just as diatonic dominants can. |
| Non-Chord Tone | A pitch that does not belong to the prevailing chord. Chromatic accidentals in applied chords are chord tones, not non-chord tones, and must be treated as tendency tones in voice leading. |
A single applied chord, or even a short string of them, does not constitute modulation. If there is no cadence confirming a new key, the primary key has not changed. Label the chord with slash notation rather than rewriting the key.
The raised pitch in an applied chord is a tendency tone and must not be doubled. Doubling it forces one voice to resolve incorrectly or creates parallel octaves. Double the root or fifth of the applied chord instead.
Secondary diminished triads follow the same rule as diatonic leading-tone triads: root position is avoided because it creates a diminished fifth above the bass. Always place the third of the chord in the bass when using the diminished triad form.
The seventh of any applied dominant or applied leading-tone seventh chord resolves down by step, not up. Moving it upward is a voice-leading error that will be flagged in error-detection tasks.
The Roman numeral to the right of the slash is the chord being tonicized, not the chord the applied chord is built on. V/V means a dominant chord that resolves to V, not a chord built on V.
The AP Music Theory exam regularly asks students to analyze passages containing chromatic chords and provide Roman numeral labels. For Unit 7 content, this means correctly identifying the applied chord type, the target chord, and any inversion, using slash notation with quality symbols (°, ø) and figured-bass numbers where required.
Free-response tasks may ask you to complete a four-voice progression that includes applied chords, or to identify specific voice-leading errors in a given passage. For secondary function chords, examiners look at whether the temporary leading tone resolves up, the chordal seventh resolves down, tendency tones are not doubled, and parallel perfect intervals are avoided.
Listening tasks may require you to identify tonicization by ear, distinguishing the chromatic pull of an applied chord from a diatonic progression or a full modulation. Recognizing the characteristic sound of V/V or vii°7/V resolving to a non-tonic chord, and noting the absence of a confirming cadence in a new key, are the key listening skills for this unit.
Open the individual guides for Unit 7 when you want a closer review of one topic.
browse guidesPractice free-response reasoning and compare your answer with scoring guidance.
practice FRQsUse unit cheatsheets for a quick visual review after you work through the notes.
open cheatsheetsEstimate your broader AP score goal after you review the course and exam format.
open calculatorAP Music Theory Unit 7 covers secondary dominant chords and secondary leading-tone chords, with a focus on tonicization. The 4 topics are: 7.1 Tonicization through Secondary Dominant Chords, 7.2 Part Writing of Secondary Dominant Chords, 7.3 Tonicization through Secondary Leading Tone Chords, and 7.4 Part Writing of Secondary Leading Tone Chords. The big idea is that non-tonic chords can temporarily sound like a tonic through tonicization, without actually changing the key. Both secondary dominants and secondary leading-tone chords (diminished triads and diminished seventh chords) create that effect. See AP Music Theory Unit 7 for practice materials matched to each topic.
The AP Music Theory Unit 7 progress check pulls questions from all four topics: secondary dominant chords, part writing of secondary dominants, secondary leading-tone chords, and part writing of secondary leading-tone chords. The MCQ portion tests your ability to identify tonicization and label secondary function chords in context. The FRQ portion typically asks you to realize or correct part writing that involves secondary dominants or secondary leading-tone chords. Practicing the progress check by topic is the most efficient approach. You can find practice questions matched to each Unit 7 topic at AP Music Theory Unit 7.
AP Music Theory Unit 7 FRQs focus on part writing secondary dominant chords and secondary leading-tone chords, so the best practice is writing out four-voice progressions that include a secondary dominant resolving to its temporary tonic. Topics 7.2 and 7.4 generate the most FRQ-style tasks: you'll be asked to realize a figured bass or correct voice-leading errors in a passage that uses tonicization. To build fluency, work through progressions that move from a secondary dominant (like V7/V) to its target chord, checking for proper resolution of the leading tone and seventh. Then try the same with diminished seventh chords from Topic 7.4. Practice sets are available at AP Music Theory Unit 7.
AP Music Theory Unit 7 practice questions, including multiple-choice and FRQ-style tasks on secondary dominants and tonicization, are available at AP Music Theory Unit 7. That page organizes practice by topic so you can target MCQs on chord identification or part-writing tasks from Topics 7.2 and 7.4 specifically. For a practice-test experience, work through questions from all four topics in one sitting: identification of secondary dominant chords, part writing, secondary leading-tone chords, and their voice-leading rules. That mirrors how the progress check and exam combine these skills.
Start with tonicization as the core concept: a secondary dominant chord makes a non-tonic chord temporarily feel like a tonic, and that idea connects all four Unit 7 topics. Once that clicks, the part-writing rules for secondary dominants (Topic 7.2) and secondary leading-tone chords (Topic 7.4) will feel logical rather than arbitrary. A solid study sequence looks like this: 1. Learn to identify and label secondary dominant chords (V/V, V7/IV, etc.) by ear and on paper. 2. Practice resolving them correctly in four voices, paying close attention to the leading tone and chordal seventh. 3. Repeat steps 1 and 2 for secondary leading-tone chords, including diminished seventh chords. 4. Do timed part-writing drills that mix both chord types so you can switch between them quickly on the exam. Visit AP Music Theory Unit 7 for topic-by-topic practice to check your progress at each step.