1834   Michael Faraday÷electrolysis experiments suggested electrical nature of
                              matter.
                   1895   Wilhelm Roentgen÷discovered X-rays when cathode rays strike the anode.
                   1896   Henri Becquerel÷discovered ãuranic raysä and radioactivity.
                   1896   Marie (Marya Sklodowska) and Pierre Curie÷discovered that radiation is
                              a property of the atom, and not due to chemical reaction. (Marie named this
                              property radioactivity.)
                   1897   Joseph J. Thomson÷discovered the electron through Crookes tube
                              experiments.
                   1898   Marie and Pierre Curie÷discovered the radioactive elements polonium and
                              radium.
                   1899   Ernest Rutherford÷discovered alpha and beta particles.
                   1900   Paul Villard÷discovered gamma rays.
                   1903   Ernest Rutherford and Frederick Soddy÷established the laws of radioactive
                              decay and transformation.
                   1910   Frederick Soddy÷proposed the isotope concept to explain the existence of
                              more than one atomic weight of radioelements.
                   1911   Ernest Rutherford÷used alpha particles to explore gold foil; discovered the
                              nucleus and the proton; proposed the nuclear theory of the atom.
                   1919   Ernest Rutherford÷announced the first artificial transmutation of atoms.
                   1932   James Chadwick÷discovered the neutron by alpha particle bombardment
                              of Beryllium.
                   1934   Frederic Joliot and Irene Joliot Curie÷produced the first artificial
                              radioisotope.
                   1938   Otto Hahn, Fritz Strassmann, Lise Meitner, and Otto Frisch÷discovered
                              nuclear fission of uranium-235 by neutron bombardment.
                   1940   Edwin M. McMillan and Philip H. Abelson÷discovered the first transuranium
                              element, neptunium, by neutron irradiation of uranium in a cyclotron.
                   1941   Glenn T. Seaborg, Edwin M. McMillan, Joseph W. Kennedy and Arthur C.
                              Wahl÷announced discovery of plutonium from beta particle emission of
                              neptunium.
                   1942   Enrico Fermi÷produced the first nuclear fission chain-reaction.
                   1944   Glenn T. Seaborg÷proposed a new format for the periodic table to show that
                              a new actinide series of 14 elements would fall below and be analogous to the
                             14 lanthanide-series elements.
                   1964   Murray Gell-Mann hypothesized that quarks are the fundamental particles
                              that make up all known subatomic particles except leptons.
 
 
 
 

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