-
400
Democritus (400BC)
Democritus was a Greek philosopher who was the first one to contribute to the history of atom. He defined the word atom from the Greek word "atomos" which means undivisible in Greek. His model of an atom was just a sphere. He did not know what made up an atom. He concluded that everything is made of atoms. -
Antoine Lavoisier
Lavoisier was a French nobleman who contributed to making the first periodic table of elements, which advocated standerized science with defined terms. From his experiments, he concluded that water consisted of hydrogen and oxygen and air consisted of nitrogen. -
John Dalton
John Dalton is an English Chemist who founded the modern Atomic Theory of Matter. The three theories which is included are: All matters are made of atoms, Atoms cannot be created nor destroyed, and Atoms can join with other substances to make new and different substances. -
J J Thomson
J J Thomson was an English physicist who discovered electrons. Through his experiment with cathode-ray tube, he concluded that atoms are negatively charged. His Plum Pudding Model showed electrons sticking to the positively charged ball. -
Marie Curie
Marie Curie was a Polish-French chemist who has contributed very important aspects to radioactivity. She discovered radium and polonium, which are on the periodic table. She and her husband were later recognized by receiving Nobel Prize for Chemistry. -
Max Planck
Max Planck contributed to the history of atom by founding the Quantum Theory. He said that energy was given off in small packets. For lights, this would be photons. Also, he found that energy in wave form is restricted to specific quantities. This helped understand energy levels of atoms. -
Albert Einstein
Albert Einstein was a German-American scientist. He contributed to the history of atom and atomic theory with his theory of relativity. He was renowned as "the father of modern physics." He is also famous for his equation e=mc^2 -
Robert Millikan
Robert Millikan was an American scientist who was interested in J J Thomson's theory that electron was 1000 times smaller than the atom. He wanted to prove that point. He did so by doing his "oil drop experiment" and he concluded that Thomson was correct. He was also involved in Quantum Theory after being inspired by Max Planck. -
Ernest Rutherford
Ernest Rutherford is famous for his experiment on alpha particles shot through gold foil. He observed some particles shooting back adn some going through the foil. He concluded that there were nucleus in every atom. From his Rutherford Model, the electrons are at the center(the nucleus) since positive charges shot back, and negative particles surrounded the positively charged particles. -
Niels Bohr
Niels Bohr is a Danish who worked with Rutherford in the same lab. He concluded that electrons traveled in specific orbits, of which Rutherford had not thought of.Bohr Model shows negatives surrounding the neutrons. -
Erwin Schrodinger
Erwin Shrodinger was an Austrian scientist who contributed to the model of the Quantum Theory. Since he disagreed with Bohr's theory, he created his own theory. He thought the way to find location and energy of an electron in an atom was calculating its probability of being a certain distance away frm the nucleus. -
Werner Heisenberg
Werner Heisenberg was a German Scientist. He concluded that both Bohr and Schrodinger were right. Heisenberg thought that the neutrons are the inner part of an atom. He also name the part that surrounded the center, he called it the cloud. -
Louis de Broglie
Louis de Broglie is a French physicist who has made a basis for developing the wave mechanics theory. He thoguht that electrons can both be like particles and waves. He also stated that waves produced by electrons contained in the orbit around the nucleus. His contributions greatly helped for developing Quantum Theory. He also won a Noble Prize for Physics. -
James Chadwick
James Chadwick is an English scientist who discovered the neutron. From previous discoveries by Rutherford, he questioned why there was a difference between the atomic mass and the number of protons. He then found out the misssing part of Rutherford's theory: the neutron.
