J. J. Thomson Discoverer of the Electron (1897).
In J.J. Thomson’s experiments he was able to bend the cathode ray (which travels in a straight line) by applying either an electric field or a magnetic field. By finding the displacement of the ray he was able to calculate electric charge mass ratio the electron. And later that they were associated with the proton H+
He described his atom as tiny negatively charged electrons that are embedded in a cloud of positive charge. He imagined the electrons are bits of plum in plum pudding.
Today it is also explained to resemble a blueberry muffin or raisin pudding.
Remember it was J.J. Thomson who identified that the atom was composed of positive and negative charges and had proposed that the atom was a solid mass of these particles.
“It was quite the most incredible event that has ever happened in my life. It was almost as incredible as if you fired a 15 inch shell at a piece of tissue paper and it came back and hit you.” Ernest Rutherford
1930’s -> ………
“Closing the book on Atomic Theory?”