Question

What experimental evidence did J.J. Thomson have for each statement?

a) Identification of electrons using cathode rays
b) Discovery of the proton through gold foil experiments
c) Observation of neutron decay in particle accelerators
d) Measurement of atomic mass through mass spectroscopy

Answer 1

J.J. Thomson's experimental evidence for the identification of electrons using cathode rays and measurement of atomic mass through mass spectroscopy are based on his observations and calculations. However, the discovery of the proton through gold foil experiments is attributed to Ernest Rutherford, and Thomson did not observe neutron decay in particle accelerators.

Step-by-step explanation:

J.J. Thomson's experimental evidence for the identification of electrons using cathode rays was based on observing that an electric field deflects the cathode rays towards the positive electrode. This showed that the cathode rays were negative charges, which Thomson concluded were streams of particles called electrons present in all elements.

Thomson's discovery of the proton through gold foil experiments is not attributed to him but to Ernest Rutherford, who performed the gold foil experiment. Rutherford shot alpha particles at a thin gold foil and observed that some of the alpha particles were deflected, which led him to propose the existence of a positively charged particle called a proton in the nucleus.

J.J. Thomson did not observe neutron decay in particle accelerators. The neutron was actually discovered by James Chadwick in 1932.

J.J. Thomson used mass spectroscopy to measure atomic mass. By studying the deflection of cathode rays in magnetic fields, Thomson was able to calculate the mass-to-charge ratio of particles, which provided a method for determining the atomic masses of elements.