Atomic Theory Timeline By imbatman101 442 BCE Democritus 428 BCE Anaxagoras and Empedocles 332 BCE Aristotle 1803 John Dalton 1898 Marie and Pierre Curie 1904 J.J. Thomson 1909 Robert Millikan 1911 Ernest Ruthford 1913 Neils Bohr 1926 Erwin (Ernest) Schrodinger 1926 1927 Werner Heisenberg 1932 James Chadwick