The electron was discovered by English physicist J. J. Thomson in 1897. Through his experiments with cathode rays, Thomson showed that these rays were composed of previously unknown negatively charged particles, which he termed "corpuscles" and are now called electrons.
Thomson's work demonstrated that electrons were much smaller than atoms and were a universal constituent of all atoms. He measured the charge-to-mass ratio of the electron and deduced its small mass, about 1/1,836 that of a hydrogen atom. The name "electron" was originally suggested by George Johnstone Stoney in 1891 but was popularized for these particles after Thomson's discovery.
Thus, J. J. Thomson is credited with the discovery of the electron as the first subatomic particle, fundamentally altering the understanding of atomic structure.
