Presentation Transcript

1. John Dalton

   By: Eli Poesnecker
2. Personal Background John Dalton was born in Eaglesfield, Cumberland, England. He lived from September 6th 1766 to July 27th 1844. In the spring of 1793 he moved to Manchester and taught mathematics and natural philosophy. A prominent Eaglesfield Quaker by the name of Elihu Robinson got John interested in problems in the fields of mathematics and meteorology. He began keeping a meteorological diary and in the next 57 years, he recorded over 200,000 observations!
3. Scientific Research and Interests John Dalton revised the atomic theory. His idea of the definition of an atom was: The smallest part of an element that can enter into a chemical reaction. Introduced the Law of Conservation of Mass- Mass is neither created or destroyed during ordinary chemical or physical reactions. Brought about the Law of Constant Composition- A chemical compound contains the same elements in exactly the same proportions by mass regardless of the size of the sample of source.
4. Scientific Research and Interests (Cont.) Made known the Law of Multiple Proportions- If 2 or more different compounds are composed of the same 2 elements, then the ratio of their masses of the 2 elements combined with a certain mass of the first is always a ratio of small, whole numbers -If two compounds are formed from the same 2 elements, then if you hold the mass of one element fixed, the mass of the other element will vary as a small whole number. -Ex: Hydrogen peroxide and water – in water, the mass is 2g hydrogen to 16g oxygen, while in hydrogen peroxide, the mass is 2g hydrogen and 32g oxygen. -The hydrogen is constant, while the oxygen is in a ratio of 1:2
5. Law of Multiple Proportions (In English) Although the previous slide may seem to be complex, it isn’t really so. When two elements can combine to form more than one compound and the same amount of the first element is used in each, then the ratio of the amounts of the other element will be a whole number. All this is saying is that the law states that they will be proportional.
6. Major Contributions Furthering atomic study and coming up with the idea that an atom looks like this.  Even though it was incorrect, it made people think more about atomic study and come up with the modern atomic theory today. He created 3 laws, as previously mentioned. He found that all atoms of a given element are identical, having the same size, mass and chemical properties. Atoms of a specific element are different than those of another.
7. Modern Atomic Theory The nucleus of an atom is made of protons and neutrons. Protons have a positive charge and neutrons have no charge. All around the nucleus is the clouds of electrons, which are made up of negatively charged electrons. All of this together makes an atom. Dalton came up with the theory: 1: All matter is made up of atoms. 2. All atoms of a certain element have the same size, mass and chemical properties. Atoms from other elements are different. 3: Atoms cannot be created, divided or destroyed. 4: Different atoms combine to make molecules. 5: In a chemical reaction, atoms are separated, combined, or rearranged. Problems with Dalton’s theory include that atoms can be divided (3) , and in number 2, some atoms have the same atomic mass. (Argon, Calcium.)
8. Dalton was the only person who was able to prove and further Democritus’ studies in over 2000 years! He opened the door for new technology and ideas about atomic study leading up to nuclear energy and weapons. Finally disproved Aristotle’s theories on the four elements (Earth, Air, Water, Fire). Led to the realization of the modern atomic theory and provided key points of it, although other points were wrong. Dalton’s Impact on Science
9. Greenaway, Frank (1966) Henry, William C. (1854) Hunt, D. M.; Dulai, K. S.; Bowmaker, J. K.; Mollon, J. D. (1995) Lonsdale, Henry (1874) Millington, John Price (1906) Patterson, Elizabeth C. (1970) Rocke, A. J. (2005) Roscoe, Henry E. (1895) Roscoe, Henry E.; Arthur Harden (1896) Smith, R. Angus (1856) Smyth, A. L. (1998) Thackray, Arnold (1972). All contributed to article: John Dalton. Retrieved from http://en.wikipedia.org/wiki/John_Dalton Mullen, Renee (2010). Created article: The Atom & the Mole. Retrieved from said article (The Atom & the Mole). Bibliography
10. Picture URLS https://reich-chemistry.wikispaces.com/file/view/F96D9_john_dalton7.jpg/44991823/F96D9_john_dalton7.jpghttp://www.campusaccess.com/images/master-of-science.jpghttp://facstaff.gpc.edu/~pgore/PhysicalScience/atom-with-electrons.gifhttp://www.pollypig.com/Images/Spheres/Yellow_solid_sphere.png