5th chords are the simplest chords to play on a guitar, but sound very 'strong'. They are commonly known as Power Chords.
The 5th chord consists of only two notes, the root note and the 5th note of the scale. This interval, as discussed earlier, is a very consonant interval. So if we were in the key of A:
we would use the root note (A) and the 5th note (E) to form our power chord. Often, the notes will be repeated to fill out the chord more. Here are some examples of how to finger a power chord, in different keys:
These shapes can be moved up and down the fretboard to be played in any key, the root note (1st) dictates what the chord name is.
These chords demonstrates the fact that the 5th note is the most important note in the scale, for various reasons. It has the closest relationship to the root note in terms of sound, and it is the note that has the best resolution to the root note.
The 5th chord is strong sounding, but does not express any 'emotion'. To add emotion to a chord we add the 3rd note of the scale. This forms what is known as a triad, and can be major or minor. We will look at these next.