Describe the contributions of the following scientists to our knowledge of atomic structure: j. j. thomson, r. a. millikan, ernest rutherford, and james chadwick

J.J. Thomson discovered and identified the electron, which was the first subatomic particle to be discovered. R.A. Millikan determined the unit charge of the electron in 1909 with his oil drop experiment. Thus allowing for the calculation of the mass of the electron and the positively charged atoms. Ernest Rutherford overturned Thomson's model in 1911 with his well-known gold foil experiment in which he demonstrated that the atom has a tiny and heavy nucleus. James Chadwick discovered the Neutron in atoms.