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400
Democritus
" By Convention bitter, by convention sweet, but in reality atoms and void." -
John Dalton
He proposed atomic theory, with spherical solid masses in motion. Atoms can't be made or destroyed. -
jj thomson
He described atoms as ball of positive charge containing a number of electron, discovered the electron. -
aston
Discovered the existence of isotopes through the use of a mass spectrograph. -
niels bohr
Developed an explanation of atomic structure that underlies regularities of the periodic table of elements. His atomic model had atoms built up of successive orbital shells of electrons. -
ernest rutherford
He is the father of nucleus physics. He developed the "gold foil experiment." Rutherford determined that the nucleus of an atom is very dense and has a positive charge. -
Heisenburg
Described atoms by means of formula connected to the frequencies of spectral lines. Proposed Principle of Indeterminacy - you can not know both the position and velocity of a particle. -
schrondinger
Viewed electrons as continuous clouds and introduced "wave mechanics" as a mathematical model of the atom. -
John Douglas Cockcroft/ Ernest Thomas Sinton Walton
Built the early linear accelerator and bombarded lithium with protons to produce alpha particles. They split the atom for the first time. This later lead to the atomic bomb that ended World War 2. Described atoms by means of formula connected to the frequencies of spectral lines. Proposed Principle of Indeterminacy - you can not know both the position and velocity of a particle. -
James Chadwick
Using alpha particles discovered a neutral atomic particle with a mass close to a proton. Thus was discovered the neutron.
