The ii chord (supertonic chord) is the triad built on scale degree 2, minor in major keys and diminished in minor keys, that functions as the strongest predominant chord, moving to V by a falling fifth in progressions like ii–V–I.
The ii chord is built on the second degree of the diatonic scale, which is why it's also called the supertonic chord. In a major key it's a minor triad (in C major: D–F–A). In a minor key it's a diminished triad (ii°), which is why composers usually soften it by putting it in first inversion (ii°6).
Its job is predominant function. The ii chord exists to set up the dominant. The root motion from ii to V is a falling fifth, the strongest root motion in tonal music, which makes ii the most direct predominant available. That's why ii–V–I is everywhere, from Bach chorales to jazz standards. You'll also see it as ii6 (first inversion) leading into a cadence, and as a seventh chord (ii7 or iiø7 in minor) when composers want extra pull toward V.
The ii chord lives in Unit 5: Harmony and Voice Leading II, which is entirely about chord progressions and predominant function. It supports learning objective AP Music Theory 5.2.A, identifying and describing harmonic function in both performed and notated music. The CED pairs it directly with the vi chord, since PIT-2.J.1 calls vi a weaker predominant. That comparison only makes sense if you know what the strong predominant is, and that's ii. When you analyze a phrase, label a progression, or part-write toward a cadence, the ii chord is usually the bridge between tonic territory and the dominant. Get the tonic → predominant → dominant → tonic cycle into your head and most Roman numeral analysis on the exam becomes pattern recognition.
Keep studying AP Music Theory Unit 5
Visual cheatsheet
view galleryThe vi (VI) Chord (Unit 5)
Per PIT-2.J.1, vi can act as a tonic substitute or a weaker predominant. The ii chord is its stronger sibling. In the classic circle-of-fifths progression vi–ii–V–I, vi hands off to ii, which hands off to V, with every root falling a fifth. One Fiveable practice question literally tests what happens to the bass line when a performer skips the vi in that sequence.
Dominant Chord (V) (Units 4-5)
The ii chord is basically a launching pad for V. Root motion down a fifth from ii to V mimics the V-to-I resolution, so ii–V–I sounds like two strong resolutions stacked back to back. If you hear a minor-quality chord right before the cadence, your first guess should be ii.
Predominant Function (Unit 5)
Predominant chords sit between tonic and dominant in the harmonic cycle. The ii chord is the textbook example of the category, with IV as the other main option and vi as the weak backup. Knowing the category means you can predict the next chord in dictation before you even hear it.
Diatonic Scale (Unit 1)
The ii chord's quality comes straight from the scale it's built on. Stacking thirds on scale degree 2 of a major scale gives you a minor triad, but doing the same in natural minor gives you a diminished triad. That's why ii° in minor keys almost always shows up in first inversion.
Expect the ii chord in Roman numeral analysis of notated scores, in harmonic dictation (where you write the progression you hear), and in the part-writing FRQs where you realize a progression in four voices. Multiple-choice stems often hand you a progression like vi–ii–V–I and ask about function, root motion, or what changes if a chord is altered or omitted. In part writing, watch the details that get graded. In minor keys, use ii°6 rather than root-position ii°, and when moving ii to V, resolve voices smoothly since the falling-fifth root motion makes parallel fifths an easy trap. No released FRQ has hinged on the term "supertonic" by name, but ii appears constantly inside the progressions you're asked to analyze and write.
Both ii and IV are predominant chords, and they even share two notes (in C major, ii is D–F–A and IV is F–A–C). The difference is strength and root motion. The ii chord moves to V by a falling fifth, the strongest pull in tonal harmony, while IV moves to V by step. A quick analysis check helps too. If the chord before V has scale degree 2 as its root, it's ii; if scale degree 4 is the root, it's IV. A ii6 chord can fool you because scale degree 4 is in the bass, so always identify the root, not just the bass note.
The ii chord is built on scale degree 2, making it a minor triad in major keys and a diminished triad (ii°) in minor keys.
It is the strongest predominant chord because it moves to V by descending fifth, the same root motion as V to I.
In minor keys, the diminished ii° chord is almost always written in first inversion (ii°6) to avoid a dissonant root-position triad.
The progression vi–ii–V–I is a descending circle-of-fifths pattern, with vi acting as the weaker predominant that feeds into ii.
Knowing the tonic → predominant → dominant → tonic cycle lets you predict that a ii chord will almost always be followed by V (or a cadential six-four resolving to V).
The ii chord, or supertonic chord, is the triad built on the second scale degree. In C major it's D–F–A (a minor triad), and it functions as a predominant chord that leads to the dominant (V).
No. The ii chord is minor in major keys but diminished (ii°) in minor keys, because the natural minor scale puts a tritone between scale degrees 2 and 6. That's why minor-key part writing uses ii°6 instead of root position.
Both are predominants, but ii moves to V by a falling fifth while IV moves by step, making ii the stronger predominant. They share two notes, so check the root. If scale degree 2 is the root, it's ii, even when ii6 puts scale degree 4 in the bass.
Almost never in common-practice harmony. The ii chord's whole job is to set up V, so ii–V–I is the expected path. Skipping V undermines the predominant-to-dominant motion that AP Music Theory analysis is built on.
Per the CED, vi can substitute for tonic or act as a weaker predominant, while ii is purely and strongly predominant. In vi–ii–V–I, vi leads to ii, which then drives to the cadence.
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