Final answer:
J.J. Thomson's experiment with the cathode ray tube revealed the existence of electrons, particles with a specific mass-to-charge ratio, signifying that atoms are divisible.
Step-by-step explanation:
J.J. Thomson's Cathode Ray Tube Experiment:
J.J. Thomson's cathode ray tube experiment led to the discovery of the electron. He conducted experiments that sent electric current through gases at low pressure within a sealed glass tube, where he observed a glowing beam, known as the cathode ray, traveling from the negatively charged cathode to the positively charged anode. Thomson's key finding was that the cathode ray was deflected towards the positive electrode in an electric field, suggesting that the rays were composed of negatively charged particles. These particles, now known as electrons, were shown to have a specific mass-to-charge ratio, which was constant regardless of the cathode material or the nature of the gas involved. Thomson's work thus provided critical evidence that atoms were divisible and that electrons were fundamental constituents of all atoms.