Certain chord progressions seem to express tonal function - some of the chords appear to be active and unstable and seek resolution, while other chords seem inherently passive, stable and resolved.
A cadential progression is one in which the tonal function of each of the chords involved is clearly audible, and which also resolves onto a chord of rest and resolution. This final chord gives a sense of closure and completion and it is known as the tonic triad.
For the tonal function of each of the chords to be apparent, each must be heard within the context of one of the eight tonal harmonic scales. For this to happen a cadence must be constructed with a minimum of three major or minor triads, or two chords when the first is either a dominant seventh or an augmented sixth.
Below I examine effective three triad and two chord cadences from each of the eight tonal harmonic scales.