If you look at a music or piano keyboard ... As you may know, major chords sound bright and happy, where as minor chords sound more melancholic or sad. Locate the 3rd of our C major triad ...

with the A minor being the Minor V chord. And then the B minor chord is the relative minor of D major. This makes for an easy way to visualise the various changing notes at your disposal.

All the chords built on other notes in the scale of C are minor, except chord VII - the notes B – D – F, which is diminished. When a seventh is added to a chord this is known as a seventh chord.