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1500 BCE
The Alchemists
They discovered important chemical elements -
430 BCE
Plato
Discovered solid forms of matter are composed of invisible elements shaped like triangles -
400 BCE
Democritus
Discovered that all matter was formed of different types of tiny discrete particles -
330 BCE
Solar System Model
It helps us understand the distances of our outer space -
Robert Boyle
He demonstrated that matter is made up of tiny particles that he called corpuscles, or as we call them, atoms. -
Antone Lavoisier
He discovered the law of conservation of mass -
Billiard Ball Model
It defines the atom to be a ball like structure as the concepts of atomic nucleus and electrons were unknown at the time -
John Dalton
He found out that all matter was comprised of invisible and indestructible atoms -
Amedeo Avogardo
He proposed that equal gas volumes contain equal numbers of molecules under the same conditions of temp and pressure -
Dmitri Mendeleev
He discovered periodic classification of elements -
JJ Thompson
He discovered the electron -
Pierre and Marie Curie
They discovered polonium and radium -
Ernest Rutherford
He discovered radioactive perpetration gave rise to the formation of gases -
Plum Pudding Model
The electrons were embedded in a uniform sphere of positive charge, like blueberries in a muffin -
Albert Einstein
Provided existence of atoms and molecules through mathematical equations -
Robert Millikan
He discovered the value of the elementary charge -
Neils Bohr
He discovered the model of an atom in which the electron was able to occupy only certain orbits around the nucleus -
Henry G.J. Mosley
He discovered the atomic number -
Werner Heisenberg
He formulated quantum mechanics -
Erwin Schrödinger
He discovered a wave equation that accurately calculated the energy levels of an electron in an atom -
Electron Cloud Model
It acknowledges the uncertainty of the electrons position and it resolves some of that uncertainty for us -
James Chadwick
He discovered the existence of neutrons