Questions: Dominant Seventh Chord Voice-Leading and Tritone Resolution

Question 1

In C major, a V7 chord (G–B–D–F) resolves to I. Which voices contain the tendency tones, and how do they move?

• A. G (root) rises to C and D (fifth) falls to E — they are the tendency tones
• B. B (leading tone) rises to C and F (seventh) falls to E — the tritone contracts inward
• C. D (fifth) and F (seventh) both resolve downward by step to C and E
• D. B (leading tone) and D (fifth) both resolve upward to C and E respectively

Answer: (B)

The tendency tones in V7 are B and F — the tritone. B is the leading tone (scale degree 7), a half-step below the tonic C, with a strong upward pull. F is the chordal seventh (scale degree 4), which wants to resolve downward by step to E (the third of I). Together they contract inward from the tritone B–F to the third C–E. G and D have no comparable harmonic urgency; they move to complete the tonic triad. This tritone contraction is the defining motion of every V7–I resolution.

Question 2

When V7 resolves strictly to I in four-part writing — both tendency tones correctly resolved — which member of the tonic chord is most often missing?

• A. The root — because C must be approached from both B and D simultaneously
• B. The third — because E is already covered by F's downward resolution
• C. The fifth — because both B→C and F→E lock two voices, leaving no remaining voice for G
• D. Nothing is missing — all four members of I are always present when V7 resolves correctly

Answer: (C)

When B rises to C and F falls to E, two voices are committed to the root and third of I. The remaining voices (G and D) typically both move to C to fill out the tonic chord, resulting in a doubled root, the third E, but no fifth (G). This incomplete tonic is standard and acceptable: the root and third define harmonic identity, and the fifth is the most expendable chord member. Forcing G into the tonic would require one tendency tone to resolve unnaturally, which weakens the cadence.

Question 3

In V7–I voice leading, the leading tone (B in C major) should ideally resolve downward to G to keep smooth, stepwise motion.

• T. True
• F. False

Answer: False

The leading tone has a powerful upward pull to the tonic (B → C) because it lies a half-step below. Resolving it downward to G is a skip of a third, not a step, and contradicts the tendency-tone logic that gives V7 its harmonic drive. In an outer voice (soprano or bass), the leading tone must rise to the tonic — this is a firm rule in common-practice voice leading. Downward resolution of the leading tone weakens the sense of arrival. The only exception is in inner voices when necessary to avoid parallel octaves or fifths.

Question 4

An incomplete tonic chord — missing the fifth, with the root doubled — is standard and acceptable when V7 resolves to I with both tendency tones correctly resolved.

• T. True
• F. False

Answer: True

When the leading tone rises (B → C) and the chordal seventh falls (F → E), no voice is available to supply the fifth (G) of the tonic chord, resulting in a doubled root. This is entirely standard in common-practice four-part writing. The fifth is the most expendable member of a triad: the root establishes the harmonic root, and the third determines major or minor quality. A complete tonic triad at the cost of a misresolved tendency tone would be a worse outcome — the tendency-tone resolution is what creates the sense of arrival.

Question 5

Explain why the tritone in the dominant seventh chord is called the 'engine' of tonal harmony.

Model answer: The tritone (B–F in G7 in C major) creates intense harmonic tension because both its notes are pulled by strong half-step or step motion toward resolution. B is a leading tone a half-step below C (tonic) and wants to rise; F is a chordal seventh that wants to fall a step to E. When V7 resolves to I, the dissonant tritone B–F contracts inward to the consonant third C–E. This specific contraction — dissonance resolving to consonance through directed half-step motion — is the defining harmonic event of tonal music. Every V7–I cadence in any key is driven by the same inward contraction, transposed. Without the tritone's urgency, dominant harmony would have no more pull toward the tonic than any other chord.

The engine metaphor captures the causal structure: the tritone is the stored tension that drives the resolution. Understanding this mechanism lets you both write convincingly in tonal idioms (always resolve the tritone correctly) and hear analytically (in any V7–I cadence you encounter, you can identify B and F moving to C and E in the appropriate key). It also explains why secondary dominants and applied chords work: borrowing a V7 from any key creates the same tritone-contraction pull toward that key's tonic.