smallest particle of matter
hypothesized that matter could be subdivided again and again until it would reach a particle that could not be divided.
hypothesized that mater was "continuous" in nature.
Divided again and again an infinite number of times and you would never reach a particle that cannot be further divided
Robert Boyle and Isaac Newton
first men to question the validity of Aristotle's hypothesis
developed the atomic theory. conceived the atom that was solid sphere, like a pool ball
discovered both electrons and protons by means of his CATHODE RAY EXPERIMENT
plum pudding model
Cathode ray experiment
electrons and protons, embedded electrodes in the ends of a sealed glass tube and passed an electrical current through it.
small pieces of metal through which electrical current is input
gold foil experiment
proved that the atom was mostly space and that all positive charge was located in a very small central
suggested the "planetary model" of the atom in which the electrons orbited the nucleus like the planets and the sun.
suggested the location of the electrons in an atom
number of protons found in the nucleus of an atom
sum of the protons and neutrons in the nucleus of an atom
a weighted average of all the masses of all the isotopes of that element by their percentage of abundance
Mass Number Charge