Thomson identified the negatively charged electron in the cathode ray tube in 1897. He knew that the electron was negative because when he put magnets on the sides of the tubes the glowing ray would be attracted to the positive side. He deduced that the electron was a component of all matter and calculated the charge to mass ratio for the electron. Thomson also proposed the "plum pudding" model of the atom. In this model, the volume of the atom is composed primarily of the positive portion (the plum pudding). The smaller electrons (the raisins in the plum pudding) are dispersed throughout the positive mass to maintain charge neutrality.
|
Cathode Ray Tube...J.J. Thompson was the first person to discover negatively charged electrons. He did this through a Cathode Ray Tube shown above.
|
Magnetized Bending...When J.J. Thompson would place a magnet next to the Cathode Ray Tube, the Cathode Ray would bend, therefore showing evidence towards a negatively charged electron.
|