Atomic Theory to the 19th Century:
Discovery of the Electron:
Through a series of experiments using cathode ray tubes (known as the Crookes’ Tube), Thomson observed that cathode rays could be deflected by electric and magnetic fields. He concluded that rather than being composed of light, they were made up of negatively charged particles that were 1ooo times smaller and 1800 times lighter than hydrogen.
The Rutherford Model:
The Bohr Model:
Influence of the Bohr Model:
Niels Bohr (1913) "On the Constitution of Atoms and Molecules, Part I"
NASA - Imagine the Universe - Background: Atoms and Light Energy