The V chord
Roman numerals in music refer to chords based on scale steps. The V chord has different meanings depending on the actual musical key. In the key of C major, the V chord is G.
Chords and intervals
The table shows how scale steps and chords are related in the key of C:
| Scale steps | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| Roman numerals | I | ii | ii | IV | V | vi | vii |
| Chords | C | Dm | Em | F | G | Am | Bdim |
The fifth scale step is G, which results in a G chord. Diatonically, the chord is played as a major as a triad and as a dominant G7 as an extended chord (in the C major key).
In other words, the C - G - F - C and C - G7 - F - C progressions will correspond with the notes in C major whereas the C - Gmaj7 - F - C progression doesn't correspond. See Key and chord chart for more examples.
In 12-bar blues, which often involve only three chords, the V chord is normally introduced last and is played during the 9th bar and sometimes in the last bar as a turnaround.
In progressions in general, the V chord often resolves into the I chord, or i chord, ("the home chord"). This is sometimes called a functioning V chord. The tension of the unstable V chord is resolved by returning home. Even more tension is created by playing a dominant V chord (V7), as in this progression: G (I) - C (IV) - D7 (V7) - G (I).
The V chord in all keys
The V chord is identical with the fifth degree of the key, a list of the V chords would look like this:
C major key = G
C# major key = G#
D major key = A
D# major key = A#
E major key = B
F major key = C
F# major key = C#
G major key = D
G# major key = D#
A major key = E
A# major key = F
B major key = F#
So, for example, in the key of A#, the V chord will be F.
The v chord in all minor keys
A similar set of relationships can be seen in minor keys:
A minor key = Em
A# minor key = Fm
Bm minor key = F#m
Cm minor key = Gm
C#m minor key = G#m
Dm minor key = Am
D#m minor key = A#m
Em minor key = Bm
Fm minor key = Cm
F#m minor key = C#m
G minor key = Dm
G# minor key = D#m
So, for example, in the key of F minor, the v chord will be Cm. The v degree is sometimes written as Vm.
The V chord in progressions
Probably the most important thing to learn is that when the V is not a triad, it's very often a dominant chord. For example, harmonizing the C major scale into four-note chords will look like this: Cmaj7 - Dm7 - Em7 - Fmaj7 - G7 - Am7 - Bm7b5. Whereas G7 fits, Gmaj7 would not fit with the notes in the scale.
Besides the fundamental I - IV - V
progression, there are some relatively common progressions that include a flat seven. Such as I - bVII - VI, which in the key of D could be D - C - G.
See also Chord theory | Music theory | The VII chord.
