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Period: 200 to
TIMESPAN
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332
Aristotle
Although this date if approximate, the information is not. Aristotle came up with the theory of all matter can only be changed with growth, decay, or motion. Objects are in turn composed of the five elements he believed existed: fire, water, earth, air, and aether. He was wrong in there are many more than 5 elements. -
Jhon Dalton (Atomic theory)
The creator of the atomic theory. Before this, the atom was only a glimpse of what we know now. This theory cemented out understanding of the atom. There is a flaw. He says all atoms are indestructable, they are not.
1) All matter is made of atoms. Atoms are indivisible and indestructible. 2) All atoms of a given element are identical in mass and properties 3) Compounds are formed by a combination of two or more different kinds of atoms. 4) A chemical reaction is an arrangement of atoms. -
JJ Thomson (nonmathmatical atomic theory)--Cathode ray
An English physicist who invented the Cathode Ray. When high energy was moved from the negative cathode plate through a vacuum sealed container to a positive plate, it created a beam of electrons. This lead to his atomic theory. This allowed solids to be made harder when clumped together. There was no large problem with his cathode ray experiment(s). The model of the ray tube is to the left. -
Ernest Rutherford
The famous gold foil experiment. This was done though experimentation. He hypothesized that the atom, when shot at a fast rate would go through the gold foil. He found out there is a nucleus in each atom. This contributed to science by proving there is a nucleus.(An important part of the atom.) The flaw was the alpha particles didn't go through the foil. this is what he thought would happen. Instead the nucleus did. HIS atomic theory was made several years later. -
Niels Bohr
Bohr came to the conclusion that atoms have a heavily charged nucleus with the electrons at a distance circling around it. This later became the first accurate model of the atom. There was close to no flaw in his thoughts with this conclusion.
His model can be see at left. -
Electron cloud model
This model represents how electrons circle in a form around the atom, in it's orbital. This was known by many scientists, but one contributed the most.(Arguably) He was Niels Bohr. He was one of the creators of this model. There is no real error ,for this is a concept. Not an experiment. -
Werner Heisenberg
Werner realized that there are many things about atoms which cannot be exactly determined nor calculated. This is mainly directed at determining an electrons location and velocity at the SAME TIME. He found it impossible to track or predict where an electron will be at any given moment. This is called the Uncertainty Principle. His predictions and "proof" were all correct. There was no error in his thoughts. (For this at least) -
Erwin Schrodinger
He came up with the Quantum mechanical atomic model which represented orbitals around the nucleus in constant motion. This was made to describe the 4 functions of waves. There was no error or flaw in this. This helps us now understand the physical build of an atom. -
James Chadwick
James Chadwick made a huge contrubution to the atom. He discovered neutrons, and the fact that they were neutral. In other words, they have no charge. This changed many things, one of which being that of how to physical atom looked. There was no flaw for this was just a discovery. -
Democritus
ONE of the first creators of the basis for the atomic theory. His theory was: "All things are made up of tiny little indistructable particled called atoms." In part he was correct, but atoms can be broken. His flaw was, in fact atoms are NOT indistructable.
