Conversation so far:
who found out that the simplest form of matter is the atom
Democritus was a Greek philosopher who was the first person to use the term atom.
did john dalton find out that the simplest form of matter is the atom
John Dalton was the first to adapt Democritus’ theory into the first modern atomic model.
when did dalton propose the first modern atomic model
Experiments with gases that first became possible at the turn of the nineteenth century led John Dalton in 1803 to propose a modern theory of the atom.
is john dalton's atomic theory accurate
John Dalton's postulate of the indivisibility of an atom in his atomic theory was proved wrong: an atom can be further subdivided into protons, neutrons and electrons.

Question: which theory is accepted in the modern day
Self-contained rewrite: which atomic theory is accepted in the modern day