Hoyo-MacNeil Period 7 Atom Timeline By kaylamacneil 450 Aristotle 450 Democritus Oct 26, 1780 John Dalton Oct 26, 1890 J.J Thomson Oct 20, 1891 James Chadwick Oct 26, 1892 Henri Becquerel Oct 26, 1903 Marie & Pierre Curie Oct 26, 1908 Robert Millikan Oct 26, 1910 Ernest Rutherford Oct 26, 1912 Neils Bohr Oct 26, 1926 Quantum Model