-
500 BCE
the Alchemists
they develop the theory that all metals are composed of mercury and sulfur and that it is possible to change base metals into gold. -
442 BCE
democritus
he created the atomic theory for the universe. what he did was he found out that everything is composed of atoms -
427 BCE
Plato
Plato introduced the atomic theory in which ideal geometric forms serve as atoms according to which atoms broke down mathematically into triangles, such that the form elements had the shape fire, air, water, earth. -
322 BCE
aristotle
the four elements, Earth, Fire, Water, and Air he believed all substances were made of small amounts of these four elements of matter. -
Robdert Boyle
he said 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 Boyle tried to construct a universal corpuscular theory of chemistry. -
lavoisier
he clarified the concept of an element as a simple substance that could not be broken down by any known method of chemical analysis and he devised a theory of the formation of chemical compounds from elements. -
john dalton
proposed that all matter was composed of atoms indivisible and indestructible building blocks While all atoms of an element were identical different elements had atoms of differing size and mass. -
dmitri mendeleev
he is the creator of the periodic table -
J.J Thomson
he was the first person to discover the electron -
the curies
the curies found out that Marie coined the term radioactivity for the spontaneous emission of ionizing penetrating rays by certain atoms. -
albert einstein
He showed that when quanta of light energy strikes atoms in the metal the quanta force the atoms to release electron -
ernest rutherford
he is known for his pioneering studies of radioactivity and the atom. -
Neils Bohr
he made numerous contribution to our understanding of atomic structure and quantum mechanics -
henry g.j moseley
he found out that experimentally demonstrated that the major properties of an element are determined by the atomic number not by the atomic weight and firmly established. -
Robert millikan
He dealt with the fundamental constituents of the universe, the forces they exert on one another, and the results produced by these forces. -
werner heisenberg
he found out that formulating quantum mechanics in terms of matrices and in discovering the uncertainty principle, which states that a particle's position and momentum cannot both be known exactly.
