In this exercise you see one chord written in a major key, with its key signature, and you must say which harmonic function it has: tonic, subdominant or dominant. Three levels, instant feedback and an explanation of each chord.
A tip to start: look in the chord for the leading tone (the note a half step below the tonic; UK: leading note). If the chord has it, it is a dominant.
How to recognize the function of a chord
For the chords in this exercise you can recognize the function with a practical three-step rule: look first for the leading tone and, if it is not there, check whether the 4th degree of the scale is present. This is a simplification designed for these chords in a major key, not a method for every chord in tonal harmony.
- Does it have the leading tone (the 7th degree of the scale)? Then it is a dominant. This is the case for V, V7 and vii°.
- If not, does it have the 4th degree? Then it is a subdominant: IV (4-6-1) and ii (2-4-6).
- If it has neither, it is a tonic: I (1-3-5) and its substitute vi (6-1-3).
For example, in C major the leading tone is B and the 4th degree is F: G–B–D has the B (dominant); D–F–A has the F and not the B (subdominant); A–C–E has neither (tonic).
Inversions do not change the function
An inverted chord keeps the same function: it depends on the scale degree the chord is built on, not on the note in the bass. At level 3 you will see triads in root position, first inversion and second inversion, and the V7 in root position, first inversion and second inversion.
Why does the iii chord not appear?
Because, depending on the context, the iii chord acts as a tonic or as a dominant. An exercise with two possible answers would not be fair, so it is not asked. The full theory is on the page about harmonic functions.
Before this exercise
It helps to know the degrees of the scale and how to build triads. After this exercise, practice with the cadence exercises, which combine these functions two at a time.