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400 BCE
Democritus
he stated atoms were uniform solid hard indistructible. -
347 BCE
plato
he believed that solid forms of matter are composed of invisible elements. -
500
the alchemists
the alchemists stated all metals were made of 2 principles sulfur and mercury. -
Robert Boyle
Robert believed that everything was composed of very tiny particles. -
Antone Lavoisier
Antone stated matter is made of atom and were not destroyed or created in a chemical reaction. -
billiard ball model
an atom is a ball like structure this was made by Dalton. -
john Dalton
john Dalton stated all matter is made of atoms which are invisible. -
Amedeo Avogadro
he said equal volume gases at the same temperature and pressure contain same number of molecules. -
Dimitri Mendeleev
he said elements are arranged to the value of atomic mass. -
Pierre and Marie curie
they stated powerful rays or energy the polonium and radium gave of particles. -
Jj Thompson
he said all atoms contain tiny negatively charged subatomic particles -
albert einsten
he said every liquid is made of molecules. -
plum pudding model
negative particles are in a sea of positive particles. -
Robert Millikan
he said electrons have a fixed measurable charge that does not vary. -
Ernest Rutherford
Rutherford said atoms are tiny, dense positively, and charged core. -
Neils Bohr
Bohr stated some physical quantity's only take discrete values. -
solar system model
describes atoms as consisting of a nucleus with a number of electrons orbiting. made by Neils Bohr -
Herny g.j mosely
Mosely stated the square root of the frequency of the x-ray emitted by an atom is proportional to its atomic number -
electron cloud model
it represented the area around the atoms nucleus where electrons are found. made by Schrödinger and Heisenberg -
Erwin Schrödinger
the behavior of electrons could be explained by treating them mathematically. -
Wenger Heisenberg
formulating quantum mechanics in terms of matrices and in discovering the uncertainty principle. -
James Chadwich
discovered the neutron.