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Jan 1, 1000
Democritus found that atoms are indivisible and was the first person to propose the idea of an atom.
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Law of conservation of matter
Antoine Lavoisier came up with the las of conservation of mass which states that the mass of an isolated system will remai the same or in other words constant all the time. -
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Law of Definite Proportions
Joseph Proust proposed the law that states that a chemical compound has the same proportion of elements by mass. They are exactly equal. Prorust proposed the law by conducting a series of experiments from 1798 to 1804. -
John Dalton now known as the father of the atomic modern theory proved and also agreed with Democritus that atoms can‘t be divided anymore.
Dalton's Theory
1. Elements are made of very small particles called atoms.
2. Atoms of an element are identical in: size, mass and other properties. Different element atoms differ in their characteristics.
3. Atoms can’t be divided, created or destroyed.
4. Atoms of different elements combine in whole number ratios to form chemical compounds.
5. In chemical reactions, atoms are combined, separated or rearranged.
Picture:http://upload.wikimedia.org/wikipedia/commons/thumb/3/3f/Dalton_John_desk.j -
Law of Multiple Proportions
John Dalton proposed the law of multiple proportions that states that if two elements form a compound between them then the ratios of the masses of the second element which actually are combined with a fixed mass of the first element will then turn into ratios of small whole numbers. -
J.J Thompson proved Atoms have particles called electrons that have a negative charge
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Plum pudding Model
Through his thorugh research, JJ Thomson and found that electrons exist in 1897 and proposed the Plum pudding or in other words the chocolate cookie model in 1904 -
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Ernest Rutherford noticed that atoms have electrons and have a nucleus through his gold foil experiment.
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Rutherford's Model
Through his own research Ernest Rutherford found that the model that JJ Thompson proposed was incorrect and needed to be fixed. So Rutherford modeled one that through his research he found to be correct and accurate. Picture:http://upload.wikimedia.org/wikipedia/commons/7/7d/Rutherfordsches_Atommodell.png -
Rutherford- Bohr Model
Rutherford and Bohr worked together to create the Bohr- Rutherford model which depicsts the atom to be small has a nucleus that is positive, is surruonded by negative electrons that travel in circular orbits around the nucleus,
Picture:http://en.wikipedia.org/wiki/Bohr_model -
Quantum Mechanical Model
According to Google quantum is an analogous discrete amount of any other physical quantity, such as momentum or electric charge. Werner Heisenberg worked and interpreted the Quantum Mechanical Model, which states that, it is impossible to calculate both the momentum and the exact location of an electron in an atom. It is only possible to calculate the probability of finding an electron if a specific location is given. -
Neils Bohr proved what Rutherford believed but also found that atoms orbit and was the first to propose the idea of a nucleus.
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Edwin Schrodinger stated that rather than electrons being distributed within an electron configuration of shells and energy levels, they were arranged in orbitals which were systematically distributed within Electron Clouds. He believed that the orbit of
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Heinsberg Uncertainty Principle
Werner heisenberg through his research found that there is a fundamental limit with accuaracy with certain pairs of phisical properties of a particle , such as position and momentum can be known at the same time. -
James Chadwick proved that the atomic nucleus contained a neutral particle which had been proposed by Rutherford 10 years earlier but was confirmed by Chadwick
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Werner Heisenberg found that atoms have a lot of energy. Particles can also borrow energy. Also found that the energy of a particle can be only measured to a certain extent
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Murray Gel-Mann Proposed the Eightfold Way
