Which conclusion did J. J. Thomson draw from his cathode ray experiments?

• A. Atoms contain negatively charged particles called electrons.
• B. Electrons orbit the nucleus in fixed energy levels.
• C. Atoms are indivisible and cannot be broken down further.
• D. The nucleus of the atom contains protons and neutrons.

Answer: (A)

Verified step by step guidance

1. Recall the historical context of J. J. Thomson's cathode ray experiments conducted in the late 19th century, which aimed to investigate the nature of cathode rays.
2. Understand that Thomson observed cathode rays were deflected by electric and magnetic fields, indicating that these rays were composed of charged particles.
3. Recognize that the deflection suggested these particles had a negative charge and were much smaller than atoms, leading to the idea that atoms are not indivisible.
4. Conclude that Thomson proposed the existence of negatively charged subatomic particles, which he called electrons, embedded within the atom.
5. Note that this discovery contradicted the earlier belief that atoms were indivisible and laid the foundation for the modern atomic model.