-
400
Democritus
He discovered the exsistence of invisible atoms charectorized only by quantive properties; size, shape, and motion. -
John Dalton
Atoms of a given element posses unique charectoristics and weight and 3 types of atoms exist. Simple elements, compound (simple molocules), and complex. -
JJ Thompson
He discovered cathode rays were negatively charged particles which he called "corpuscles". He claimed these were things from which atoms were built up. They had a mass of about 100 times smaller than a hydrogen atom. -
Cathode Ray Experiment
Thompson cocluded that particles were a universal componet of matter. He also discovered that cathode rays could be deflected by an electric field. -
Ernest Rutherford
He thought that all the alpha particles with a charge +2e were brought together into a little ball by Columbus repulsive force, which has the charge +Ze. -
Neils Bohr
He discovered that electrons travel only in certain orbits and that only in a discrete set of stable states. This explained the atomic structure of the atom as "successive orbital shells of electrons", -
Isotopes are used in catscans
Francis Aston discovered that for different elements the atomic mass isn't the same for all the atoms of the element. The experiment led to the making of the catscans. -
Schrodinger
He identified the electron cloud model as the probable location of moving electrons. -
Chadwick
He discovered a particle within the nucleus that has a mass similar to that of a proton. Thus, he is credited with discovering the nuetron. -
Cockroft/Walton
Split the atom.
Split the nucleus at the heart of the atom. -
Built the Atomic Bomb
Bomb was dropped on Japan to end World War Two.
