Music Theory Notes

Any cadence ending on the Five chord is considered a half cadence.

So in the key of C,

C D E F G
1 2 3 4 5

G triad is the five.

Authentic cadence is a 5-1.

So in a key of C

Authentic Cadence: G-C

Plagal Cadenceis a 4-1

So in a key of C

Plagal Cadence: F - C

Deceptive cadence is 5- any number that is not 1.

so the deceptive cadence in the key of C is

5-4-3-2