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460
Democritus
Democritus used scientific reasoning and advanc logic to come up with the idea of an "Atom". -
Period: 460 to
Atomic Theory
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Antoine Lavoisier
Antoine Lavoisier demonstrated that air is composed of 2 parts and he named both oxygen and helium & he helped construct the metric system. -
Joseph Louis Proust
Joseph Louis Proust gave results of his chemical analyses in terms of percent weights In 1794 & he recognized that the proportions of the compounds of a chemical compound are always the same . -
Law of Definite Proportions
This states that a compound made of two elements will be made equally by the two elements. -
Daltons Atomic Theory
Daltons Atomic Theory was all matter is made of atoms, atoms are indivisible and indestructible. -
John Dalton
John Dalton developed the first useful atomic theory of matter in 1803 & believed compounds involved chemical combination of atoms. -
Dmitiri Mendeleev
Dmitiri Mendeleev invented 3 elements gallium, scandium , and germanium in 18711 & he put 63 known elements into a peiodic table based on atomic mass . -
Eugen Goldstein
His research and discovery lead to Thompson’s experiment with cathode tubes and further developed the knowledge of the atom. -
Cathode Ray Tube
This experiment proved that that the negative charge and the ray were inseparable and intertwined. -
J.J Thomson
Among many MANY other expirements and discoveries, possible his most important was that he insulted water molecules so that they would dissociate, and gave us a better indepth understanding of what an atom was. -
Marie Curie
Marie Curie invented 2 new elements radium and polonium in 1903 & she showed that the atom was divisible. -
Plum Pudding Atomic Model
J.J. Thomson figured that most of an atom consisted of empty space and random negitive and postive particles. This was disproved within 5 years. -
Gold Foil Experiment
Hans Geiger shot atoms at gold foil to see if they would all pass, but some did not, which disproved J.J. Thomsons "Plum Pudding Model" and proved that was more than empty space in an atom. -
Robert Millikan
Robert Millikan proved the exsistence of the electron cloud through his "Oil Drop Experiment". -
The Rutherford Model
The Rutherford Model created a model of a atom that showed the mass in the nucleus like planets orbiting around the sun. Rutherford did an experiment that most of the mass of an atom was in the nucleus and electrons orbited around the nucleus -
Neils Bohr
Niels Bohr made an atomic diagram in 1913 & he postulated that electrons travel in fixed orbits around the atoms nucleus and further explained how electrons emit or absorb energy. -
Henry Mosely
Henry Mosely developed the application of the x-ray in 1913 & his discoveries resulted in a more accurate positioning of elements in the periodic table. -
Bohr Planetary Model
Neils Bohr came up with the plantary model the helped further explian how atoms are organized. -
Quantum Mechanical Model
Quantum Mechanical Model uses complete shapes , electron clouds, volumes of space where there is likely to be electrons , based on probability, not certainty , developed by Niels Bohr, based on mathematics , it is a model that shows matter also has properties associated with waves. -
Erwin Schrodinger
He used math to firgure where an electron would be inside an atom, creating a better understanding of the inside of the atom. -
James Chadwick
James founded the idea of the neutron through redoing expirment from other scientist. -
Ernest Rutherford
Ernest Rutherford discovered alpha and beta rays and set forth the laws of radioactivity decay 1871-1937 & he postulated the nuclear structure of the atom. -
Lise Meitner
Considered the "Mother of the Atom Bomb" becuase she discovered that you can split an atom while she was working with the army to create a better bomb.