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332
aristotle
all matter is made up of atoms -
400
democritus
beieved that atoms were hard and unifrom and moved in infinite space -
427
plato
believed that atoms can break down into geometric shapes -
lavoisier
found that matter is made of atoms and matter can be neither created or destroyed -
john dalton
atoms of the same element are the same but different elements have different atoms. -
The Alchemists
layed down the buiding blocks of the periodic table -
newlands law of octaves
found out that putting elements in order in increasing atomic weight will group them in groups of 7 -
mendeleeves pd. table
found the physical and chemical properties of elements were related to their atomic mass -
photoeletric effect
was disovered by henreich rudolf found that when eletricmagnetic radiation asses through a electron and the electron takes the radiation -
discovery of radioactivity
henri becquarel he found the element radium a highly radioactive element. -
discovery of electrons
J.J. Thompson found the electrons in cathode rays -
plum pudding model
it is a historical odel of the atom show how the elcrons are all over the place. -
plancks quantum theory of light
different atoms can absorbs different amounts and energy -
rutherford gold foil experiment
ernest rutheford found tht putting postiviley charged atoms through a piece of gold found that atms are mostly open space -
charge of the electron
jj thompsons experiment showed that all atoms have a postive negative and neutral charged particle. -
Robert Millikan
found the charge of and electron by using the falling drop method -
bohr's planetary model
was a basic over making the elctrons pictured as plantes orbiting the atom by nick bohr -
mosleys atomic numbers
found the tomic number is the number of postively charged particles. -
discovery of the proton
a experment was performed by ernest rutherford and he split a atom revaling a postiveley charged particle -
schrodinger equation
found and equation the energy and place of the electron. -
heisenberg uncertainty principle
leaurate werner hesienberg came up with the theory that we can not now the exct speed of a particle -
discovery of the nuetron
sir james chadwick discovered a uncharged particle.