You can keep extending chords making 6th, 7th, 9th, 11th, 13th chords, and sus4 chords. G is then 5 steps away from the root (C) making it the 5th. The 1st note (in this case C) is called the root, after that you count steps away, starting with C - making the 3rd E. Since triad chords are built by using every other note from the one you begin on - a C Major chord would be CEG. For example in the key of C the scale would be CDEFGABC. The scale numbers would look like this I ii iii IV V (the 5th should have lines above to show its Major) vi vii(o) I. The remaining chords are minor with the exception of the 7th which is diminished. The I, IV, and V are the only major chords in a traditional major scale. The formula to make a Major scale is the same for every single Major key. In western music chords are traditionally built by using every other note beginning on each scale degree - giving you a choice of 7 diatonic chords in a Major scale. Upper case represents a Major chord, lower case are minor chords, and lower case with a little circle in the upper righthand corner of the Roman numeral is diminished. The scale degrees are numbered with Roman numerals so that you can use upper and lower case letters. Each scale degree represents a potential chord. Each note in the scale is called a scale degree. A Major scale has 7 different notes and then ends back on 1, making a total of 8 notes.

Minor 7 flat 5 chord