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300
Democtritus
Said matter was made of invisible particles called atoms -
John Dalton
Propoaed an atomic theory with spherical solid masses in motion. -
JJ Thompson
Described the atom as a ball of positive charge containing a number of electrons. Discovery of electron. -
Ernest Rutherford
Used his "gold foil" experiment to determine that the nucleus of the atom is very dense and had a positive charge. Thus, discovering the proton. He also assumed that the electons were outside the nucleus of the atom. -
Neils Bohr
Explained the atomic structure of the atom as "successive orbital shells of electrons." Model known as the Bohr Plalnetary Model. -
Cockcroft and Walton
Split the atom. -
Schrodinger
Identified the electron cloud model as the probable location of moving elecrtons. -
Chadwick
Discovered a particle within the nucleus that has a mass similar to that of a proton. Thus, he is credited with discovering the neutron. -
Build atoic bomb
Bomb was dropped on Japan to end World War 2. -
First underground nuclear test
The first underground nuclear test, code named Rainier, 1.7 kilitons. -
Worst neclear power plant accident
The most serious in the United States commercial nuclear power plant operating history, even though it led to no deaths or injuries to workers in the plant or anywhere near it.