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Democritus's theory stated that:
All matter consists of atoms.
Atoms are invisible, indestructible, homogeneous, and can’t be destroyed.
Atoms differ in size. -
Democritus's atomic theory states that:
All matter consists of atoms.
Atoms are invisible, indestructible, homogeneous, and can’t be destroyed.
Atoms differ in size. -
John Dalton's Atomic Theory states:
All matter consists of atoms.
Atoms are invisible and indestructible.
All atoms of a given element are identical in mass and properties.
Compounds are formed of two or more atoms.
A chemical reaction is a rearrangement of atoms. -
J.J Thomson identified the negatively charged electron. He also calculated the charge to mass ratio of an electron.e/m = -1.76 x 108 coulombs/g
He proposed the plum pudding atomic model. -
He determined the charge of an electron with his Oil Drop Experiment(1909), which helped calculate the mass of an electron and positively charged particles.
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He proposed the nuclear atom as a result of the gold-foil experiment. He discovered that positive charge and mass are found in the small center of the atom while the majority of the volume is occupied by electrons. in 1920, he first referred to the hydrogen nucleus as a proton and proposed the neutron.
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He discovered that electrons travel in their own separate orbits.
An electron's orbit size is determined by its energy. -
Officially discovered the neutron in 1932.
