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Discovery of the Electron
Thompson placed cathode tubes in electric and magnetic fields. Thomson knew the cathode rays must be made of some small particle, which he dubbed a "corpuscle." In a later ingenious experiment, Millikan was able to find the electron charge and from the charge to mass ratio: 9.11 x 10-31 kg. One electron volt is the energy that an electron gains when it travels through a potential difference of one volt (1 eV = 1.6 x 10-19 Joules.
www.youtube.com/watch?v=Rb6MguN0Uj4 -
Discovery of the Nucleus
Ernest Rutherford, performed a famous experiment in order to put the plum pudding model of the atom to the test using the gold foil experiment. The locations of the excited states differ for each nucleus. The excitation energy, Ex, depends on the internal structure of each nucleus.
www.youtube.com/watch?v=dNp-vP17asI -
Discovery of the Proton
Ernest Rutherford discovered the nucleus by demonstrating that positive charges were concentrated in a very small fraction of an atoms' volume. In 1919 Rutherford discovered that he could change one element into another by striking it with energetic alpha particles. The mass of the proton is about 80–100 times greater than the sum of the rest masses of the quarks that make it up.
www.youtube.com/watch?v=kBgIMRV895w -
Discovery of the Neutron
James Chadwick used scattering data to calculate the mass of this neutral particle. He repeated the creation of the radiation using beryllium, used better approaches to detection, and aimed the radiation at paraffin following the Paris experiment. The mass of a neutron can be deduced by subtracting proton mass from deuteron mass, with the difference being the mass of the neutron.
www.youtube.com/watch?v=_7DAlvRI1M4
