Arpeggio is just a fancy way of saying that you play certain notes in a certain order, usually sequentially. A mode (like minor or lydian) determines which not

Arpeggio is just a fancy way of saying that you play certain notes in a certain order, usually sequentially. A mode (like minor or lydian) determines which notes are played. Let's take the notes in C major as an example. If you start with the C and play it up to C', then you get C major. If you play the same notes but starting at D, and up to D', then you get the D Dorian scale. Start with E, you get the E Phrygian scale, start with F, you get the F Lydian scale, etc.. Those scales or modes are all either major or minor (as the difference between major and minor is determined by the interval between first and third note), modes 1,4,5 are major and 2,3,6,7 are minor. If someone plays a piece in E Phrygian mode, how would you know that it is? By looking at a piano keyboard, you would see that she only plays white keys, which tells you that the tonic/root is C major. Since a piece written in E Phrygian will most likely have progressions or melodies that start/end with an E, you would know that it's not C major, but E Phrygian. If you pay close attention to scores written for mystery movies (or the Simpson's), you will notice that it sounds outlandish or alien. That's because they use the Lydian scale. They might really only use C major notes, but starting a melody at the fourth (F) makes it sound completely different. A major chord (example C major) is made up of three notes: first is the chord's tonic (C), second is a major third higher than the tonic (E), third is a quint higher than the tonic (G). A minor chord is similar to a major, but the second note is only a minor third higher than the tonic. Using C minor as an example, the second note is Eb. The chords that OP progresses over are the modes/scales I described above. If you set the tonic/root to C major, then the 5th mode would be G mixolydian (which happens to be a major mode), or the 6th would be good old A minor. Still, the only notes that are played are those that occur in the C major scale - the chords just use different starting points.