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Period: 370 to
Democritus
-Democritus was the first person to suggest that matter could nt be infinitely divided
-Couldn't find out what holds atoms together -
Period: to
John Dalton
-Revived the term 'atom'
-'Atoms are the smallest particles of matter and ae indivisible and indestructible -
Period: to
Sir WIlliam Crookes
-His theory led to the creation of the T.V.
-His theory is that the ray of light's negative particles were found in all forms of matter -
Period: to
J.J. Thompson
-Designed a series of CRT experiments at Cambridge to determine the ratio of the particles charge to its mass -
Period: to
Robert Millikan
-Determined that the magnitude of the charge of the electron was 1.602x10-19 coulombs.
-Discovered the mass of the electron using the known charge/mass ratio: 9.1x10-28 g -
Period: to
Ernest Rutherford
-Studied how positively charged α-particles interacted with a solid matter
-He designed an experiment to see if α-particles would be deflected as they passed through a thin sheet of gold foil. -
Period: to
James Chadwick
-Demonstrated that the nucleus had another neutral subatomic particle, the neutron
-Chadwick won the 1935 Nobel prize for his discovery of the neutron. -
Period: to 450
Aristotle
-Did not agree with Democritus that atoms move through empty space
-Completely denied the existence of atoms due to personal ideas and nature