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Dalton's Model of the Atom / J.J. Thomson / Millikan's Oil Drop Experiment / Rutherford / Niels Bohr / DeBroglie / Heisenberg / Planck / Schrödinger / Chadwick

 

 

J J Thomson and the Cathode Ray Tube

 

 

From MIT 3.091-Lec 3 Donald Sadoway

J.J. Thomson-Professor of Physics and Director of Cavendish Lab at Cambridge University

Electrons are distributed throughout uniformly charged positive sphere of atomic dimensions. J.J. did not like the term electron. He called the electron, the "corpuscle" of electrical charge. Another British electrochemist John Stoney called it the "electron"  from the Greek term "Elecktra" which is the Greek word for amber. Amber when rubbed builds up static charge.

 

When investigating cathode rays using a highly evacuated discharge tube he was able to use the calculated velocity and deflection of the beam to calculate the ratio of electric charge to mass of the cathode ray. This was found to be constant regardless of the gas used in the tube and the metal of the cathode and was approximately 1000 times less than the value calculated for hydrogen ions in the electrolysis of liquids. The electron is discovered, J J Thomson publishes his discovery of a subatomic particle common to all matter.

The New Model of the Atom-Thompson knew atoms were neutral, so there must be a balance of negative and positive particles. This new model is referred to as the Plum Pudding Model.
Dalton J.J. Thomson

Plum Pudding

 

Dalton's Model of the Atom / J.J. Thomson / Millikan's Oil Drop Experiment / Rutherford / Niels Bohr / DeBroglie / Heisenberg / Planck / Schrödinger / Chadwick

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