The Discovery Of Electron

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  • April 29, 2023
9th Chemistry Ch#02 Atomic Structure The Discovery Of Electron

Cathode Rays – The Discovery of Electron

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Apparatus setup:

  1. The discharge tube consists of a glass tube with metal electrodes fused in the walls and gas filled in it.
  2. Through a glass side-arm air can be drawn with a pump (Vacuum pump).
  3. The electrodes are connected to a source of high voltage (10,000 Volts).

cathode rays

Working:

When a high voltage current was passed through the gas, shiny rays were emitted from the cathode which travels towards the anode as shown in the diagram below. These rays were given the name “cathode rays” as they originated from the cathode.

Properties Of Cathode Rays:

The cathode rays were studied in detail and their properties were determined, which are given

below:

  • These rays travel in straight lines perpendicular to the cathode surface.
  • They can cast a sharp shadow of an opaque object if placed in their path.
  • They are deflected toward the positive plate in an electric field showing that they are negatively charged.
  • JJ. Thomson discovered their charge/mass (e / m) ratio.
  • Light is produced when these rays hit the walls of the discharge tube.
  • It was found that the same type of rays was emitted no matter which gas and whichcathode was used in the discharge tube.

    Conclusion:

    Different scientists tried different discharge tubes with different electrodes and different gases but they found the same results. Experiment shows that these particles could be produced by any kind of material. Cathode rays consist of particles that are known as ELECTRONS.

    Quiz

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