Watch the Chapter 3: 3-Note Arpeggios online guitar lesson by Frank Vignola from Modern Method for Guitar
Chapter 3 is similar to Chapter 2, but instead of playing the major scale we play arpeggios; first vertically, then horizontally, beginning with the C major arpeggio. An arpeggio is made up of the same notes used to play the chord of the same name. The difference is that when you strum a chord, you play all of the notes simultaneously; when you play an arpeggio, you pick each note one at a time. The most basic chord is a triad. As its name implies, it has 3 notes.
Build arpeggios and chords by selecting every other note of the scale, known as intervals called 3rds. You can identify any interval by counting the letter names in the scale inclusively. So, to build a C major triad we count 3 letter names C-D-E; we know that E is a 3rd away from C. From E we count 3- E-F-G and we know that G is a 3rd away from E. Therefore, the C major triad is built with the 1st, 3rd and 5th, or every other note of the major scale: C-E-G.
Since chords and arpeggios are made up of the same notes, a major arpeggio contains the 1st, 3rd and 5th notes of the major scale, which are C- the root, E -the 3rd and G-the 5th. Arpeggios are building blocks for solos and important to master.