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460
Democritus
In 460 BC Democritus discovery of the atom was made. His method for dicovering the atom was that he took a seashell and broke it in half & kept breaking it,till he made fine powder. He said that an atom looked like small tiny particles -
Dalton
Dalton made his discovery in 1803, he discovered that evaporated water exist in air as an independent gas. His method was mixture of gases to determine what effect properties of the individual gases. -
JJ Thomson
He discovered that electricity passing through a gas caused the gas to give off particles that were too small to be atoms.Thomson proposed thst electrons were sprinklede around inside atoms like raisins in a loaf of raisin bread. -
Rutherford
Rutherford lauched positively charged helium ions at a veery thin gold foil.They found something quite unexpected. Most of the helium ions passed right through the foill with no deflection at all. -
Bohr
He proposed energy levels of electrons are discrete and that the electrons revolve in stable orbits around the atomic nucleus but can jump one energy level to another. He also prposed the concept of energy levels to explain the spectrum of hydrogen -
Heisenberg and Schrodinger
They discovered that you cannot know by measurement the position and momentum of a particle stimultaneously. They invented the new quantum theory of phycis.
