-
335
Aristotle
He thought that all materials on Earth were not made ofatoms, but of the four elements, Earth, Fire, Water, and Air -
460
Democritus
Atoms are solid,homegeneous,indestructible, and invisble. -
Antonie Lavosier
in the study of chemical reactions -
Period: to
Antonie Lavosier
in the study of chemical reactions -
Joseph Proust
He first published his Law of Definite Proportions -
John Dalton
All matter is made of atoms. Atoms are indivisible and indestructible. 3) Compounds are formed by a combination of two or more different kinds of atoms. -
Amadeo Avagadro
best known for his hypothesis that equal volumes of different gases contain an equal number of molecules -
William Crookes
British chemist and physicist noted for his discovery of the element thallium and for his cathode-ray studies, fundamental in the development of atomic physics -
-
J.J. Thomson
discovered the electron in a series of experiments designed to study the nature of electric discharge in a high-vacuum cathode-ray tube, an area being investigated by numerous scientists at the time. -
-
Max Planck
is best known as the originator of the quantum theory of energy for which he was awarded the Nobel Prize in 1918. -
Albert Einstein
Published the famous equation E=mc 2 -
Robert Millikan
Measured the charge of an electron -
Madame Curie
naturalized-French physicist and chemist who conducted pioneering research on radioactivity -
Henry Moseley
But in his classic study of the x-ray spectra of elements, he established the truly scientific basis of the Periodic Table by arranging chemical elements in the order of their atomic numbers. -
Ernest Rutherford
he postulated the nuclear structure of the atom -
Niels Bohr
proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well defined quantities. -
Werner Heisenberg
contributed to the atomic theory by including quantum mechanics, the branch of mechanics, based on quantum theory, used for interpretating the behavior of elementary particles and atoms -
Erwin Schrodinger
He made the first model of the atom -
Louis deBroglie
French physicist best known for his research on quantum theory and for predicting the wave nature of electrons -
James Chadwick
discovered the neutron
