Leucippus of Miletis and Democritus produce first written record proposing that matter consisted of indivisible particles with nothing between them. They called this Atomos.
Antoine-Laurent Lavosider discovers the “Law of the conservation of mass”
Joseph Proust proposes “Law of definite proportions”
John Dalton produces his atomic theroy
JJ Thompson identifies electrons and produces “Plum Pudding” model of atom
Sir James Chadwick discovers Neutrons
Ernest Rutherford proposes that there is a central neuclus consisting of protons and is orbited by electrons
Neil Bohr proposes his version of the atomic structure