Which scientist is credited with the discovery of the electron?

• A. Robert Millikan
• B. Ernest Rutherford
• C. J.J. Thomson
• D. Niels Bohr

Answer: (C)

Verified step by step guidance

1. Understand that this question is about the historical discovery of the electron, a fundamental particle in chemistry and physics.
2. Recall that the electron was discovered through experiments involving cathode rays, which are streams of electrons observed in vacuum tubes.
3. Identify the scientist who conducted these cathode ray tube experiments and concluded the existence of the electron as a particle smaller than an atom.
4. Recognize that J.J. Thomson is credited with this discovery in 1897, based on his measurements of the charge-to-mass ratio of the electron.
5. Note that Robert Millikan later measured the electron's charge, Ernest Rutherford discovered the nucleus, and Niels Bohr developed a model of the atom, but none of these are credited with discovering the electron itself.