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560 BCE
democritus
He theorized that all material bodies are made up of indivisibly small “atoms.” Aristotle famously rejected atomism in On Generation and Corruption. -
500 BCE
the alchemists
that all metals are composed of mercury and sulfur and that it is possible to change base metals into gold. Dalton's most important contribution to science was his theory that matter is composed of atoms of differing weights and combine in simple ratios by weight. -
428 BCE
Plato
Plato was so impressed with this discovery that he was convinced that atoms of matter must derive from these five fundamental solids. But at the time the Greek periodic table consisted only of earth, water, air and fire. -
384 BCE
aristotle
he only thing Aristotle discovered that caries on to the modern atomic theory is the fact that there are elements, which is implied in Aristotle’s theory. Despite this, Aristotle’s theory did contribute too the atomic theory in another way which was a negative way. This contribution was the delay caused to the emergence of the atomic theory. -
Robert Boyle
Boyle's Law for which he remains most famous. This states that if the volume of a gas is decreased, the pressure increases proportionally. Understanding that his results could be explained if all gases were made of tiny particles. -
lavoisier
he is credited as being the first person to make use of the balance. He was known for his skills in experimentation and loved to separate the oxygen molecule from HgO. This led him to come up with the Law of Conservation, which states that matter is unable to be made or destroyed. -
dmritri mendeleev
He made great contributions to the atom by creating the first periodic table of elements. He concluded that there are still more elements to be discovered that are to be added to the periodic table. In mostly every science you learn something about the periodic table, these teachings are credited to Dmitri Mendeleev. -
john dalton
By far Dalton’s most influential work in chemistry was his atomic theory. Attempts to trace precisely how Dalton developed this theory have proved futile -
jj thomson
J.J. Thomson is credited with the discovery of the electron, the negatively charged particle in the atom. He is known for the Thomson atomic theory. Many scientists studied the electric discharge of a cathode ray tube. It was Thomson's interpretation that was important -
the curies
her contributions to the study of radium and radiation were instrumental to the future development of the atomic bomb. -
robert millikan
determined the unit charge of the electron in 1909 with his oil drop experiment at the University of Chicago. Thus allowing for the calculation of the mass of the electron and the positively charged atoms -
albert Einstein
Albert Einstein is famous for his work that contributed to the important advancements in science such as space exploration, applications of light and atomic energy. His theories led scientists to understand new ways to look at energy, matter, gravity, space and time. -
henry mosely
contribution to the science of physics was the justification from physical laws of the previous empirical and chemical concept of the atomic number. -
ernest rutherford
a New Zealand-born British physicist who was among the leading scientists of the twentieth century. He made a paramount contribution to the sciences of Physics and Chemistry through his study of radioactivity and structure of the atom. -
Werner Heisenberg
Heisenberg's contributions to the atom are that he calculated the behavior of the electrons around the atom with the Uncertainty Principle. Heisenberg changed the way people look at atoms now because he helped clarify the amount of electrons to determine how many electrons an atom contains. -
Neils Bohr
Niels Bohr proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well defined quantities. Electrons should move around the nucleus but only in prescribed orbits. When jumping from one orbit to another with lower energy, a light quantum is emitted.
