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Democritus
He said that everyone and everything is made up of tiny particles called atoms. -
Dalton
He stated almost the same thing as Democritus but also stated that atoms could be distinguished based on their atomic weights. -
Seaborg
He discovered some transuranium elements. The elements were plutonium, americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium and element 106 that was later named seaborgium. -
Thomson
The particles in the gases were universal and that he stated that all matter is made up of particles smaller than atoms that he called ‘Corpuscles’ -
Rutherford
He found two radiation types in uranium that he called “alpha” and “beta”. Alpha was identical to the nucleus of a helium atom and the beta was the same as an electron. -
Bohr
He discovered that atoms give off electromagnetic radiation as a result of electrons on different energy levels. -
Chadwick
He discovered a neutral atomic particle. It was later called the neutron.
