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500 BCE
Democritus (460 B.C- 370 B.C)
In 500 B.C he said that matter was made up of tiny indivisible particles,that between an atom there it was an empty space, that atoms were indestructible, that atoms would always be in motion and that there are different types of shapes of them. -
John Dalton
In 1803 he said that atoms were elements composed by tiny particles, that compounds had like the same proportion of elements. that all the elements that the atoms contained were identical, and that they cant be destroyed or separated in a chemical reaction. -
Eugen Goldstein
He was working on his own investigations of dischanfge tubes he discovered the proton. -
Joseph John Thomson
AKA J.J thomson, he discovered the electron in 1897and then he proposed a model for the structure of the atom. This led the invention of the mass spectrograph. -
Ernest Rutherford
In 1911, his opinion of an atom was basically made of a tiny, dense core called nucleus, in which all the mass is accumulated, negative constituents, called electrons, circulate at some distance. -
Niels Bohr
In 1913 Bohr modified the Rutherford theory by requiring that the electrons move in orbits of fixed size and energy. The energy of an electron depends on the size of the orbit and is lower for smaller orbits. -
James Chardwick
He discovered the neutrons in atoms in 1932 and was awarded a Nobel prize for physics in 1935.
