
John L. answered 06/12/19
Music Tutor
I think that the use of the terms strong and weak chords are misleading. The difference between tonal and atonal music is the theory that in tonal music, there are tones and chords that hold more weight, than others, but in atonal music each tone is treated as equals.
I would say that there is a hierarchy in terms of importance. The tonic (I) and dominant (V) chords are the most important because without them we don't have a tonality. The sub-dominant (IV), supertonic (ii), mediant (iii), and sub-mediant (vi) are chords that lead to the dominant chord. The leading tone can be used used as a dominant replacement, but never used as a cadence.