Timeline

** History of the Atom Timeline ** Add dates, names, and accomplishments of each scientist to this section to complete a class "History of the Atom" timeline.


 * Date || Scientist || Accomplishment or breakthrough ||
 * 1803 || John Dalton || Proposed the atomic theory. ||
 * 1897 || J.J. Thomson || Studied "canal rays" and found they were associated with the proton H + . ||
 * 1897 || J.J. Thomson || Used a [|CRT]to experimentally determine the charge to mass ratio [|(e/m)]of an electron =1.759 x 10 8 coulombs/gram. ||
 * 1922 || Niels Bohr || Developed an explanation of atomic structure that underlies regularities of the periodic table of elements. His atomic model had atoms built up of sucessive orbital shells of electrons. ||
 * 1932 || James Chadwick || Using alpha particles discovered a neutral atomic particle with a mass close to a proton. Thus was discovered the neutron. ||