Who provided the first experimental evidence that atoms contain subatomic particles?

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

Answer: (D)

Verified step by step guidance

1. Understand the historical context of atomic theory: Initially, atoms were thought to be indivisible particles, but later experiments showed they contain smaller components called subatomic particles.
2. Recall the key experiments related to atomic structure: J.J. Thomson conducted the cathode ray tube experiment, which led to the discovery of the electron, the first identified subatomic particle.
3. Recognize that Robert Millikan measured the charge of the electron, Ernest Rutherford discovered the nucleus, and Niels Bohr developed a model of the atom, but none provided the first evidence of subatomic particles.
4. Identify that J.J. Thomson's work was the first to provide experimental evidence that atoms are not indivisible but contain smaller negatively charged particles (electrons).
5. Conclude that the correct answer is J.J. Thomson because his cathode ray experiments demonstrated the existence of electrons, proving atoms have subatomic particles.