Jacqueline's Digital Timeline By Jacqueline.Perez15 Sep 14, 2015 1809 at least 47 elements were discovered Sep 14, 2015 1680 Robert Boyle discovered phosphorus and it became famous. Sep 14, 2015 1863 John Newlands divided the 56 discovered elements into 11 groups Sep 14, 2015 1869 Dmitri Mendeleev started the development of the periodic table, arranging chemical elements by atomic mass Sep 14, 2015 1894 William Ramsay and Lord Rayleigh discovered noble gases, which were added to the periodic table as group 0 Sep 14, 2015 1897 J.J. Thomson discovered electrons Sep 14, 2015 1900 Henri Becquerel discovered electrons and beta particles are the same thing Sep 14, 2015 1945 Glenn Seaborg identified that elements with >92 atomic number are usually placed below the periodic table
