Which physicist discovered the electron in 1897 through cathode-ray experiments?

J. J. Thomson discovered the electron in 1897 through cathode-ray experiments.

At the Cavendish Laboratory in Cambridge, Thomson studied rays produced in evacuated glass tubes. By observing how the rays were deflected by electric and magnetic fields, he concluded that they consisted of particles much smaller than atoms. He measured their charge-to-mass ratio and argued that these particles were universal constituents of matter.

Thomson called the particles corpuscles, although electron soon became the standard term. His work showed that atoms were divisible, challenging the older idea that atoms were indivisible building blocks. He received the 1906 Nobel Prize in Physics for investigations of the conduction of electricity by gases.

Robert Millikan later measured the electron’s charge in his oil-drop experiment, while Ernest Rutherford established the nuclear model of the atom. Those achievements are related but are not the discovery of the electron itself.