Chord Construction Theory (cont.)
On "F" the mode we have is:

(notes in an "F" major, or 4 or IV chord)

On "G" the mode is:

(notes in a "G" major, or 5 or V chord)

Many times you will hear the 5, or V chord called a 7th chord, i.e. G7. Let's look at the "G" mode again:

(* adding the 7th note of the mode makes it a G7 chord)

This is called an "extension." When you get into jazz and pop music, you play more harmonically advanced chords by adding extra notes to the chord stack to give it texture. Other extensions with the "G" chord could be:

* 9th Chord * 11th Chord * 13th Chord

You could even get fancier and either sharp or flat the 5th and 9th notes to get a really way out sound. But this is not jazz theory, at least for now, so we will move on.