Major chords are formed from the first, third, and fifth tones of a major scale. So in the key of “C,” for example, the C Major Chord consists of the notes C, E, and G, since those are the first, third, and fifth tones from the C Major Scale (C - D - E - F - G - A - B - C). In root position, a major chord is also formed from stacking a major third and minor third (whereas in a minor chord, the relationship is reversed - with a minor third and major third being stacked starting on the root note).