-
Isaac Newton
Proposed a mechanical universe with small solid masses in motion. -
John Dalton
Proposed an "atomic theory" with spherical solid atoms based upon measurable properties of mass. -
Michael Faraday
Studied the effect of electricity on solutions, coined term "electrolysis" as a splitting of molecules with electricity, developed laws of electrolysis. Faraday himself was not a proponent of atomism. -
George Stoney
Introduced the term electron and estimated the charge carried by a single hydrogen atom. How this contributed to our understanding of the atom. -
Jospeh Thomson
Invention of the mass spectrometer. He explains that it is difficult for charged ions to attract each other through insulating water molecules, so they dissociate. -
Nels Bohr
He suggested that when an atom is excited or heated, electrons can jump to higher levels, and when the atom cools down , they drop down to lower levels. -
James Chadwick
discovered the neutron, named because of its lack of electrical charge, which was previously an unknown particle in the nucleus of an atom. -
Rutherford
Rutherford proposed the nuclear atom as Rutherford proposed that all of the positive charge and all of the mass of the atom occupied a small volume at the center of the atom and that most of the volume of the atom was empty space occupied by the electron. -
JJ Thomson
J. J. Thomson identified the negatively charged electron in the cathode ray tube in 1897. He deduced that the electron was a component of all matter and calculated the charge to mass ratio for the electron.
