-
500 BCE
The Alchemists
that all metals are composed of mercury and sulfur and that it is possible to change base metals into gold. -
427 BCE
Plato
Plato introduced the atomic theory in which ideal geometric forms serve as atoms, -
400 BCE
Democritus
Democritus matter consists of invisible particles called atoms and a void empty space. -
384 BCE
Aristotle
he made pioneering contributions to all fields of philosophy and science, he invented the field of formal logic, and he identified the various scientific disciplines and explored their relationships to each other. -
Robert Boyle
He discovered Boyle's law, which shows that the volume and pressure of a gas are proportionally related -
Lavoisier
Lavoisier is known for discovering the role oxygen plays in combustion and helped construct the metric system. -
John Dalton
john Dalton was best known for introducing the atomic theory into chemistry. He thought atoms were the smallest particles of matter and envisioned them as billiard pool balls. -
Dmitri Mendeleev
Mendeleev found that, when all the known chemical elements were arranged in order of increasing atomic weight, the resulting table displayed a recurring pattern, or periodicity, of properties within groups of elements -
The Curies
she made her own experiments on uranium rays and discovered that they remained constant, no matter the condition or form of the uranium -
J.J. Thompson
Thompsons model showed an atom positively charged medium, or space with negatively charged elections in the medium. -
Robert Millikan
Robert Millikan was a physicist who discovered the elementary charge of an electron using the oil-drop experiment -
Ernest Rutherford
Ernest Rutherford discovered the nucleus of the atom in 1911 -
Neils bohr
Bohr proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well defined quantities. -
Henry G. J. Mosley
Through this, he discovered a systematic relation between wave- length and atomic number. This discovery is now known as Moseley's Law. -
Albert Einstein
he is best known for his equation E = mc2, which states that energy and mass (matter) are the same thing, just in different forms. -
Werner Heisenberg
this model is a way to help visualize the most probable position of electrons in an atom. The model is the current accepted model of an atom.
