-
500
Democritus
460 - 370 BC Came up with the term atomos. 1st person to suggest that matter could not be infinitely divided.
Didnt figure out what hold atoms together. -
505
Aristotle
384 BC- 322 Took over the same ideas as Democritus -
Dalton
Revised Democritus's idea and based it off his personal scientific research. -
Sir William Crookes
continued research on cathode ray tubes led to a discovery of stem charged particles .particles had a negative charge -
J.J. Thompson
To determine the ratio of a particle's charge ti its mass, Thompson created a series a experiments to determine the ratio.
concluded that the mass of the particle was much less than that of the Hydrogen atom.
Thompson designed a model of what the shaoe of an atom might look like, it is in a shaoe of a sphere and composed a distributed postive charge. The negatively charged electrons were around the positively charged sphere, similar to what an electron may look like today. -
Robert Milikan
To determine the charge of an electron, Milikan invented an oil drop apparatus.
He determined the charge if the electron , which is 1.602x10-19
It's equated to a sing charge of unit of negative charge, which makes e-1. -
Ernest Rutherford
Studied how positively chargedd a- particles was aware of the plum pudding model. Calculated that an atom was mostly just empty space for electrons to move around. Identified a simpler and more comercially viable means of detecting radio waves that had been previously established. -
James Chadwick
He proved the existence of neutrons, the elementary particle without any electrical charge and a fundamental building block of the atom's nucleus. He refined his concept of the nucleus to include that it contained positively charged particles called proton.
