Which subatomic particle is J. J. Thomson credited with discovering?

• A. Neutron
• B. Positron
• C. Electron
• D. Proton

Answer: (C)

Verified step by step guidance

1. Recall the historical contributions of J. J. Thomson in the field of atomic structure.
2. Understand that J. J. Thomson conducted experiments with cathode rays, which led to the discovery of a negatively charged particle smaller than an atom.
3. Identify that this particle is the electron, which was the first subatomic particle discovered, changing the model of the atom from indivisible to composed of smaller parts.
4. Recognize that the neutron was discovered later by James Chadwick, the proton was identified by Ernest Rutherford, and the positron was discovered by Carl Anderson.
5. Conclude that J. J. Thomson is credited with discovering the electron.