Chemistry
With reference to the discovery of the structure of an atom, explain in brief - William Crookes experiment for the discovery of cathode rays, followed by - J.J. Thomsons experiment pertaining to the constituents of the cathode rays.
State which sub-atomic particle was discovered from his experiment.
Answer
William Crookes Experiment:
William Crookes passed an electric discharge through a discharge tube containing a gas at low pressure. Blue rays were emitted from the cathode [negative plate] which were called cathode rays.
J.J. Thompson's Experiment:
In his experiments, J.J. Thomson studied the characteristics and constituents of cathode rays and observed that the rays have kinetic energy & cast a shadow of an object in their path. They were deflected by a positively charged plate.
Discovery of electron:
This proved that the cathode rays consisted of negatively charged sub-atomic particles called electrons.
Related Questions
Draw a neat labeled diagram representing an atom. Name the three sub-atomic particles in the atom & represent them symbolically showing the mass & charge of each. State where the sub-atomic particles are present in the atom.
Explain in brief - Goldstein's experiment which led to the discovery of the proton and - Lord Rutherford's experiment which led to the discovery of the atomic nucleus.
'Electrons revolve around the nucleus in fixed orbits or shells called energy levels'. State how these energy levels are represented.