Leading tone resolution is the voice-leading principle that scale degree 7 (the leading tone), sitting a half step below tonic, resolves up to scale degree 1, especially when it appears in an outer voice of a dominant-function chord moving to tonic.
The leading tone is scale degree 7, the note one half step below tonic. That half step is the whole point. It's so close to tonic that your ear hears it as unfinished, like a sentence that stops right before the last word. Leading tone resolution is what happens when the music delivers that last word, with scale degree 7 stepping up to scale degree 1.
In AP Music Theory, this isn't just an interesting tendency, it's a voice-leading rule. When the leading tone appears in a dominant-function chord (V or vii°) and that chord moves to tonic, the leading tone resolves up to tonic, and this is required when the leading tone is in an outer voice (soprano or bass). It's also why you never double the leading tone in four-part writing. If two voices both held scale degree 7, both would need to resolve up to scale degree 1, creating parallel octaves. One tendency tone, one resolution.
Leading tone resolution sits at the heart of Units 4 and 5, where you learn four-part (SATB) voice leading and harmonic progressions. It's the engine behind dominant function. The reason V-I sounds like an arrival is largely because scale degree 7 in the V chord pulls up to scale degree 1 in the I chord. It also explains why you raise scale degree 7 in minor keys (Unit 2). Without that raised note, the v chord has no leading tone, no pull, and no real dominant function. The concept then scales up in Unit 7, where secondary dominants work by creating a temporary leading tone to a chord other than tonic. If you understand leading tone resolution, secondary dominants stop feeling like a new topic and start feeling like the same trick aimed at a new target.
Keep studying AP Music Theory Unit 7
Visual cheatsheet
view galleryHarmonic Function and Dominant Chords (Units 4-5)
Dominant function basically is the leading tone. V and vii° both contain scale degree 7, and its pull toward tonic is what makes those chords demand resolution. When you label a chord as dominant-function, you're really saying it carries a leading tone that wants to go home.
Cadences (Unit 4)
An authentic cadence (V-I) gets its conclusive sound from the leading tone resolving to tonic. A perfect authentic cadence goes further and puts that arrival in the soprano. Half cadences feel suspended partly because the leading tone is left hanging, never resolving.
Harmonic Minor and the Raised 7th (Unit 2)
Natural minor's seventh degree (the subtonic) sits a whole step below tonic, too far away to pull. Raising it a half step creates a true leading tone, which is the entire reason harmonic minor exists and why you raise scale degree 7 when writing V chords in minor keys.
Secondary Dominants (Unit 7)
A secondary dominant like V/V borrows the leading tone trick. Its chromatically raised note acts as a temporary leading tone to the chord being tonicized, and it resolves up by half step exactly like scale degree 7 resolves to tonic. Same rule, different destination.
This concept gets tested two ways. In multiple choice, you'll identify the leading tone in a key, recognize why a raised scale degree 7 appears in minor, or spot voice-leading errors like an unresolved or doubled leading tone. The bigger payoff is on the part-writing FRQs (figured bass realization and Roman numeral realization). When you write a V or vii° chord resolving to tonic, the leading tone in an outer voice must step up to scale degree 1, and you must never double the leading tone. Readers check for exactly these errors, so a single frozen or doubled leading tone costs points. Quick self-check before moving on: find scale degree 7 in every dominant-function chord you write and trace where it goes.
Both are tendency tones in a V7 chord, but they pull in opposite directions. The leading tone (scale degree 7 of the key, the third of the V7 chord) resolves UP by half step to tonic. The chordal seventh (the dissonant 7th above the root of the chord, scale degree 4 of the key) resolves DOWN by step to scale degree 3. In a V7-I progression you handle both at once. Mixing them up is one of the fastest ways to lose voice-leading points, so remember it as leading tone up, chordal seventh down.
The leading tone is scale degree 7, a half step below tonic, and it resolves up by half step to scale degree 1.
In four-part writing, a leading tone in an outer voice (soprano or bass) must resolve up to tonic when a dominant-function chord moves to I.
Never double the leading tone, because two voices resolving up to tonic would create parallel octaves.
In minor keys, raise scale degree 7 to create a real leading tone; otherwise the v chord lacks dominant function.
Leading tone resolution is what makes authentic cadences sound final, and unresolved leading tones are why half cadences sound open.
Secondary dominants (Unit 7) work by creating a temporary leading tone that resolves up by half step to the tonicized chord.
It's the principle that scale degree 7 (the leading tone), a half step below tonic, resolves upward to scale degree 1. It's strongest in dominant-function chords like V and vii° moving to tonic, and it's the source of the 'pull' you hear at authentic cadences.
Not in every single case. On the AP exam, the firm rule is that a leading tone in an outer voice (soprano or bass) must resolve up to tonic when the dominant chord moves to I. In an inner voice, it can occasionally move elsewhere (like down to scale degree 5 to complete the tonic triad), and that's accepted.
They resolve in opposite directions. The leading tone (scale degree 7 of the key) resolves up a half step to tonic, while the chordal seventh (scale degree 4 of the key, the 7th of the V7 chord) resolves down by step to scale degree 3. A correct V7-I requires both.
Because the leading tone is a tendency tone that must resolve up to tonic. If two voices doubled it, both would resolve to the same note and create parallel octaves, which is a graded voice-leading error on the part-writing FRQs.
Natural minor's seventh degree (the subtonic) is a whole step below tonic, so it has no half-step pull. Raising it a half step turns it into a true leading tone, which gives the V chord its dominant function and makes V-i cadences sound conclusive.
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