The electron

What was discovered

By measuring the electric and magnetic deflection of cathode rays, Thomson demonstrates that they are particles with a charge-to-mass ratio a thousand times greater than hydrogen's and that they are the same whatever the gas: the first subatomic particle. The atom ceases to be indivisible.

Wiechert (Königsberg) and Kaufmann (Berlin) obtained similar measurements in 1897; it was Thomson who stated that they were universal constituents of matter.

What it led to

• Atomic physics and models of the atom
• Electronics (valve, transistor)
• Electron theory of conduction and chemistry
• Particle physics

Built on

• Faraday's laws of electrolysis1833-1834
• Cathode rays1869-1879
• Lorentz and Zeeman's electron theory

Made possible

• Nagaoka's Saturnian atomic model1904
• Mass spectrometer1912–1919
• Electron microscope1931–1933
• Thermionic valve

📄 Original publication

Links