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Democritus
Had a theory that everything was made of little tiny things called "Atoms" -
Antoine Lavoisier
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Law of Conservation of Mass
States that mass can neither be destroyed or created in chemical reactions. Was discovered by Antoine Lavoisier. -
John Dalton
recognized and named oxygen and hydrogen and disproved the phlogiston theory. also wrote the first extensive of elements, and helped to reform chemical nomenclature -
Daltons Atomic theory
Dalotns theory was based on the premise that atoms of differnt elements could be distinguished by diffrences in their wights.
All matter is composed of atoms.
atoms can not be made or destroyed.
All atoms of the same elemnt are identical. -
Dmitri Mendeleev
Formulated a periodic table of the elements similar to the one used today -
Cathode Ray Tube
A cathode is a terminal or electrode at which electrons enter a systmem, such as an electrolyctic cell or an electron tube. The Cathode is responsible for making televisions. -
JJ Thomson
discovered the electron also found cathode rays, which are beams of light that follow an electrical discharge in a high-vacuum tube. Also found that the atom was neutral so there had to be a balance of the negative and positive particles. Also theorized that the negative charges were like plums in a ‘pudding’ model -
Plum pudding atomic model
Was a model of the highly densed nucleus made up of electrons, neutrons, and protons. -
Robert millikan
His oil drop experiment confirmed the existence of the electron and accurately determined its charge. His experiment on the photoelectric effect established the wave/particle dual nature of light. -
Rutherford Model.
Bombarded gold foil with alpha particles. A source which undergoes alpha decay and is placed in lead box with a small hole in it. -
Henry Moseley
Established a truly scientific basis of the periodic table of the elements by sorting chemical elements in the order of their atomic numbers. -
Niels Bohr
Formed one of the first ever atomic bomb during world war II. Also proposed that the idea of “complementarity” that thing may have a duel nature (They can both be a wave and particle) also introduced the Quantum theory. -
Bohr Planetary
Shows the atom a small positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus. -
Erwin Schrodinger
Explained the movement of electrons in an atom he concluded that it was a wave of motion he called this idea Wave Mechanics. His discovery was the first to explain the idea. In 1944 he wrote the book “what is life?” which was about the problems of genetics -
Ernest Rutherford
in 1911 Rutherford discovered that atoms were not independent they are controlled by a nucleus. He also discovered that there is something smaller than an atom. in 1917 Rutherford “split the atom” discovering that atoms are made of more than one “part”. The “Gold Foil Experiment” was one of his most know experiments -
Gold Foil Experiment
set up so that a beam would fire the beam od alpha particles where they then landed on the screen provided. Each particle was to easily passed. All the alpha particles passed except for the ones that would be slightly deflected from its path by one or two degrees. -
Quantum Mechanical Model
is based on mathematics. Says matter also has properties associated with waves. -
James Chadwick
was an english physicist who was awarded the 1935 nobel prize in physics for his discovery of the neutron in 1932. -
Electron Cloud Model
The electron cloud model is an atom model where electrons are no longer depicted as particles moving around the nucleus in a fixed orbit.
