Neutrons were discovered by

Analysis

The question asks for the scientist credited with the discovery of the neutron, a subatomic particle found in the nucleus of an atom.

Concept Explanation

To answer this, we look at the history of atomic structure:

• John Dalton: Proposed the atomic theory, suggesting atoms are indivisible spheres.
• Michael Faraday: Known for his work on electromagnetism and electrolysis, not subatomic particle discovery.
• Ernest Rutherford: Discovered the nucleus of the atom through his famous gold foil experiment.
• James Chadwick: In 1932, he performed experiments bombarding beryllium with alpha particles. He observed that the radiation produced was not affected by electric or magnetic fields, proving it consisted of neutral particles with a mass similar to that of a proton. He named these particles neutrons.

Step-by-Step Solution

1. Evaluate Option A (Faraday): Incorrect. His work focused on electricity and magnetism.
2. Evaluate Option B (Dalton): Incorrect. He proposed the existence of atoms but did not identify subatomic particles.
3. Evaluate Option C (James Chadwick): Correct. His experimental evidence in 1932 confirmed the existence of the neutron.
4. Evaluate Option D (Rutherford): Incorrect. While he discovered the nucleus and the proton, he did not discover the neutron.

Exam Tip

To remember this for your JAMB exam, use the mnemonic "Chadwick had a neutron". Also, remember the "big three" of atomic discovery:

• J.J. Thomson: Electron
• Ernest Rutherford: Proton (and the Nucleus)
• James Chadwick: Neutron