https://padlet.com/203674yssdorg/ovjn46yujzcn History of the Atomic Model en-us 2016-11-10 19:07:37 UTC 2025-05-22 17:22:20 UTC hello@padlet.com 204084 https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/136857194 Democritus was a Greek philosopher around 400 B.C. who thought that if one were to cut objects, there would be a point in which it could not be cut any more. He called these parts Atomos, and theorized that they would be spherical in shape and indivisible. The shape and size would determine what type of substance it created.
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Image]]> 2016-11-10 19:10:10 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/136857194 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/136857719 Beginning in 1897, J. J. Thompson provided the idea that atoms are made of even smaller particles than what was previously thought. He found out this information by observing how how electric currents travel through different gases, and he found that as they travel through these gases, they gave off rays that consisted off negatively charged particles. From this, Thompson concluded that  the negative charges he was seeing were coming from within the atom, because the gas was uncharged, so atoms were more divisible than they had thought. From this, he was able to make a comparison for the average person to comprehend what an atom was like and compared that structure of an atom to that of plum pudding.
Image    Info]]> 2016-11-10 19:11:14 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/136857719 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/136857876 In 1908, Earnest Rutherford began his work to find answers as to what an atom is and what its components are. To do so, he shot a line of positively charged particles at gold foil that was only 2,000 atoms thick, hence the name "Gold Foil Experiment." In this experiment, most of these particles passed through the sheet of gold. However, occasionally the positively charged particles would bounce back towards the gun. This suggested to Rutherford that there are positively charged ions in the gold sheet because positive particles bounce off of each other as if they were solids. Contrary to previous beliefs, atoms did not resemble plum pudding, but are instead mostly open space. Rutherford established that there is a nucleus in atoms, which is very small, dense and contain the positively charged particles, whereas the electrons were dispersed around the edge.
Image    Info]]> 2016-11-10 19:11:32 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/136857876 204084 https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/136859667 Aristotle was a rival philosopher of Democritus, who, with his student Plato theorized that everything in the universe was made up of four elements: fire, water, earth, and air. Although he was completely incorrect, he was more popular and his theory was accepted throughout ancient Greece.
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Image]]> 2016-11-10 19:15:26 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/136859667 204084 https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/136863636 John Dalton was the first scientist with evidence to prove the atomic theory. He is known as the father of atomic science. He believed that everything is made up of atoms, which vary between elements. He thought atoms had no smaller parts, and could not be split or created. He also believed that by the arrangement of atoms, different elements could be created.
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Image]]> 2016-11-10 19:24:17 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/136863636 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137265775 After observing and studying the different theories of atomic structure, Niels Bohr decided to take it a step further by putting each of the electrons into their specific energy level in 1913. According to Bohr, electrons followed definite orbits around the nucleus of an atom, these orbits were dependent upon the amount of energy present in a particular electron.
Bohr also presented that when electrons quickly move from place to place,  they emit or absorb radiation.
Image    Info    Info]]> 2016-11-14 04:44:33 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137265775 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137269091 The "quantum" or "electron cloud" theory has been conceived from many years of research and studying and took many scientists to develop, who have come to the conclusion that an atomic model is based off of wave quantum mechanics. These principles proved Bohr wrong in that electrons do not follow a definite path and are actually impossible to know exactly where they are at any given time. However, scientists can produce a rough estimate of where an electron may be based on the amount of energy it possesses. As thought by previous scientists, an atom consists of a nucleus surrounded by enough electrons to make the atom neutral. Although the electrons do not move in a definite pattern as they swirl around the nucleus at a very fast pace, they do not travel in random movements; electrons with high energy can be found on the outskirts of an atom, but electrons with low energy can be found closer the nucleus.
Image    Info]]> 2016-11-14 05:45:14 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137269091 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137270265 In 1774, Antoine Lavoisier began to experiment with fire and studied what happened to an object after it had been burned along with the rest of the process of burning. This was a very significant study because from it derived The Law of Conservation of Mass, which states that matter can neither be created or destroyed in either a physical or chemical reaction, which birthed the beginning of modern chemistry.
Fun Fact: Antoine Lavoisier was beheaded in 1794 for his relationship with the daughter of an executive of a tax firm.
 Image   Info    ]]> 2016-11-14 06:09:12 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137270265 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137272210 In 1793, Joseph Proust came up with the Law of Definite Proportions, which is the idea that the element ratio in a compound is always the same. This law was made as a result of his concerns with inorganic binary compounds, which are compounds that lack carbon and have exactly two different elements, like  sulfates, sulfides, and metallic oxides. His research was then published in 1795 in Spanish journals. This proved to be helpful for Dalton, for he later proposed the Law of Multiple Proportion and eventually his atomic theory, which was aided by Proust's research on the matter. However, Proust was not supported by everyone, for French chemist, Claude-Louis Berthollet, argued against many of Proust's points. The controversy was ended with Dalton's previously mentioned atomic theory.
Image    Info    Info    Info]]> 2016-11-14 06:31:41 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137272210 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137274099 In approximately 1909, Robert Millikan conducted his well known "Oil Drop Experiment" with colleague, Harvey Fletcher. Together, the two began trying to measure the charge of an electron by placing charges on drops of oil and measured the strength needed of an electric field to keep the drop from falling.  Millikan knew the weight of the drops he used and could figure out how much gravitational force was acting on the drop, so ultimately he could establish what electric charge the drop had. No matter the charge on the different drops,  Millikan concluded that it would always be a multiple of -1.6 x 10 -10 C.
Image    Info]]> 2016-11-14 06:56:59 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137274099 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137276285 2016-11-14 07:20:56 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137276285 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137277237 2016-11-14 07:28:29 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137277237 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137277548 2016-11-14 07:31:21 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137277548 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137278280 2016-11-14 07:37:36 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137278280 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137278811 Image]]> 2016-11-14 07:42:37 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137278811 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137279162 Image]]> 2016-11-14 07:45:55 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137279162 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137279458 Image]]> 2016-11-14 07:48:25 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137279458 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137279668 Image]]> 2016-11-14 07:49:59 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137279668 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137279985 Image]]> 2016-11-14 07:52:14 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137279985 203674yssdorg https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137280442 Image]]> 2016-11-14 07:55:31 UTC https://padlet.com/203674yssdorg/ovjn46yujzcn/wish/137280442