Which part of dalton's atomic theory was disproved by further scientific research?

The main assumption made by Dalton that was disproved by further scientific research is that atom was indivisible. He conceived the atoms as the minimun portion of matter that could be obtained and that when you got to the atom unit it did not contain other parts.

As we know, further scientific research showed that atoms contain smaller partes: electrons, protons and neutrons. And also protons and neutrons are formed by smaller parts (quarks).