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Known as the father of modern chemistry. He discovered the element oxygen. He proposed the Law of Conservation of Mass. He came of with the first table of elements.
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States that matter can neither be created nor destroyed in a chemical reaction
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John Dalton actually put forth the atomic theory. He stated that all elements are made up of tiny indivisible particles, known as atoms.
Atoms of the same element are identical
Atoms of different elements are different from each other and can be identified by their weights.
Chemical reactions occure due to rearangment, combination, or seperation of atoms.
Atoms combine in the ratio of whole number, 1:1, 1:2, 2:3
Atoms of 2 or more elements combine to form compounds -
All matter is composed of atoms
Atoms cannot be made or destroyed
All atoms of the same element are identical
Different elements have different typess of atoms
Chemical reactions occur when atoms are rearranged
Compounds are formed from two or more elements -
Created a periodic table according the elements atomic mass and atomic numbers.
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J.J. Thomson used this to discover negativley charged particles now known as electrons. A cathode ray tube is a vacuum tube in which images are produced when an electron beam hits a phosphorescent surface.
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J.J. Thomson discovered the electron and eventually neutrons
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Atomic model proposed by J.J. Thomson. The plum pudding model consisted of positively charged fluid that contain negatively charged particle scattered throughout.
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He determined the charge of single electrons
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Ernest Rutherford conducted this experiment. A beam of alpha particles was aimed at a piece of gold foil and then it was observed where the particles landed on the screen.
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Proposed that an atom consisted of a dense charged core with electrons floating in a cloud around it.
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Performed gold foil expirement and came up with the atom having a central charge and electrons floating around.
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Came up with the Bohr model. He proposed that all the mass was in the nucleus and electrons going around the nucleus in a fixed orbit.
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Contributed more to the modern periodic table, discoverd more accurate positioning in the periodic table.
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Proposed by Niels Bohr. In the Bohr model the protons and neutrons are located in a dense core called a nucleus. The electrons move in circles around the nucleus
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Took the Bohr model one step further. Came up with the electron cloud, and introduced the concept of sub-energy levels.
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Electrons defined as standing waves. Correctly defines electrons movement in relation to the nucleus.
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Represents the history of where the electron has traveled leaving a 'cloud' behind it.
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Proved existance of neutron
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Democritus was a Greek philosopher who proposed that all things originate from tiny indivisible particles, which he called atom, and the differed according to their shape and arangment. He also proposed that atoms cannot be destroyed. He came up with this about 492 BC.
