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Early transuranium elements. After the discovery of the neutron by Chadwick in 1932, the group led by Fermi in Rome. began bombarding different elements with neutrons to study the radioactivity induced through. (n,() reactions. The decay characteristics of the radioactivity in neutron-irradiated uranium was. interpreted to indicate that some of the products were probably transuranium elements. Similar. conclusions were reached by other research groups; for example in 1937 Meitner, Hahn and.
In 1869 Russian chemist Dimitri Mendeleev started the development of the periodic table, arranging chemical elements by atomic mass. He predicted the discovery of other elements, and left spaces open in his periodic table for them.In 1886 French physicist Antoine Bequerel first discovered radioactivity.Thomson student from New Zealand Ernest Rutherford named three types of radiation; alpha, beta and gamma rays.n 1894 Sir William Ramsay and Lord Rayleigh discovered the noble gases, which were added to the periodic table as group 0. In 1897 English physicist J. J. Thomson first discovered electrons; small negatively charged particles in an atom. John Townsend and Robert Millikan determined their exact charge and mass.