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Democritus
He discovered that matter is made of indivisible particles called atoms. -
John Dalton
He proposed atomic theory with spherical solid masses in motion -
Ernest Rutherford
Discovered the by doing an experiment to determine that the nucleus of an atom is very dense and had a postive charge. -
Cambrige College
During Rutherford's year in college, he and Thomson were able to demonstrate that x-rays cause the air molecules to break apart. -
JJ Thomson
Described the atom as a postive charged ball containing a number of electrons -
Neils Bohr
Explained the atomic structures of the atom as "successive orbital shells of electrons." He also used a model called Bohr Planetary Model. -
Schrodinger
Identified the electron cloud model as the probable location of moving electrons. -
Chadwick
Discovered a particle within the nucleus that has a mass similar to that of a proton which was a neutron. -
Enrico Fermi
Built the 1st nuclear reactor at the University of Chicago. -
Warning: Atomic Bomb
Einstein sent a letter to Pres. Roosevelt warning him of the destructive outcome that would happen if the bomb was used. But Roosevelt never read it and it was too late when both bombs were dropped.