AP Music theory - Inversions

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Root of the triad is the bass note

I6

is the first inversion of a triad where the third of the chord is the lowest note.

I6/4

is a triad in second inversion, where the fifth of the chord is the bass note.

I7

is a seventh chord that adds a seventh degree above the root of the triad.

I6/5

is a 7th chord in first inversion with the third in the bass.

I4/3

is a 7th in root position, where the 5th of the chord is the bass note.

I4/2

the 7th of the 7th chord is in the bass

Half cadence

A two chord phrase ending with the V (usually followed by an authentic cadence)

Authentic cadence

Occurs when a phrase ends in V or a vii° chord resolving to I.

Perfect authentic cadence (PAC)

a type of authentic cadence where the V is used instead of the vii°, both chords are in root position, and the highest note of the I/i chord is the tonic of the scale

Imperfect authentic cadence (IAC)

Doesn’t meet the requirements of an authentic cadence

Plagal cadence

when a cadence ends with the IV/iv going to I/i

Deceptive cadence

a V chord going to something other than I/i