You are harmonizing in G major. What quality is the chord built on the 2nd scale degree (A)?
AMajor — A is a common note shared with many chords in G major
BMinor — the diatonic structure of every major key produces a minor triad on scale degree ii
CDiminished — it is adjacent to the tonic and therefore unstable
DMajor — it shares two notes with the I chord and therefore inherits its quality
In G major, building a triad on A using only notes from the key gives A–C–E. The interval from A to C is a minor third (1.5 steps), so the chord is minor. This is not specific to G major — the diatonic structure of every major key produces a minor triad on the 2nd degree (ii). The chord quality follows from the interval structure of the scale, not from any choice or convention.
Question 2 Multiple Choice
A composer wants a major chord on the 2nd scale degree in C major and uses D–F#–A instead of D–F–A. This chord:
AIs perfectly diatonic — composers can choose the quality of any chord in their key
BIs a non-diatonic chord that introduces F#, a note outside C major, making it a chromatic or borrowed chord
CIs the standard ii chord in C major, since D major is closely related
DIs allowed because F# belongs to the G major scale, which shares six notes with C major
Diatonic chords are built using only the notes of the key. In C major, the note F is natural (not F#), so the triad on D is D–F–A (minor). Using F# introduces a chromatic alteration that makes this a non-diatonic chord — a technique available to composers, but one that leaves the diatonic system. The quality of diatonic chords is fixed by the key's interval structure, not a free choice.
Question 3 True / False
In any major key, the chords built on scale degrees I, IV, and V are always major triads.
TTrue
FFalse
Answer: True
This follows from the interval structure of the major scale (W-W-H-W-W-W-H). The whole-step and half-step pattern guarantees that building triads on degrees 1, 4, and 5 using only scale tones always produces major thirds above those roots, yielding major triads. This is true regardless of the key — C major, F# major, Bb major, or any other.
Question 4 True / False
The chord built on the 7th scale degree of a major key (vii) is a minor triad.
TTrue
FFalse
Answer: False
The chord on the 7th scale degree is a *diminished* triad, not minor. In C major it is B–D–F. The interval from B to D is a minor third (correct for minor or diminished), but the interval from B to F is a diminished fifth (tritone), not a perfect fifth. A minor triad has a perfect fifth above the root; a diminished triad has a diminished fifth. The vii° symbol (with the degree symbol) specifically denotes diminished quality.
Question 5 Short Answer
Why do the diatonic triads in every major key always have the same chord qualities on the same scale degrees — I and IV and V always major, ii and iii and vi always minor, vii always diminished — regardless of which major key you are in?
Think about your answer, then reveal below.
Model answer: Because all major keys share the same interval structure (W-W-H-W-W-W-H). When you build a triad on each scale degree using only the notes of that key, the pattern of whole and half steps determines whether the third above the root is major (2 whole steps) or minor (1.5 steps), which in turn fixes the chord quality. The same interval structure in every key produces the same quality pattern on every degree.
This is why Roman numeral analysis is so powerful — the numerals describe relationships that hold across all major keys. Once you know that ii is always minor and V is always major, you can read and transpose progressions without recalculating from scratch in each new key.