was greek word and it means “not able to be divided.” The next scientist who worked with atoms was John Dalton‚ he lived from 1766 to 1844. His main theories were that elements combine in certain proportions based on mass to form compounds‚ each element has a different atom and a different atomic weight‚ all atoms of the same element are perfectly identical‚ and atoms cannot be created or destroyed in chemical reactions. He also had his own
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Isotopes and average atomic mass Isotope: element variations with different atomic mass but same atomic number Isotopic Abundance: the relative amount in which each isotope of an element Calculating: given 2 isotopes of an element [B: 10.01u] [B: 11.01u] 1) Given average atomic mass: 10.81u If given percentages‚ you can find average atomic mass by adding each portion 2) Set variables for unknown values Let x represent % abundance for 10/5 B Let 1-x represent % abundance for 11/5 B Calculate:
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the effective operation and good management of a police department; (2) planning is the essential element of decision –making; (3) effective planning can eliminate or reduce potential catastrophe resulting from manmade and natural disasters; (4) decision making can usually be described in three types of theoretical models rational‚ incremental‚ and heuristic none of which defines all of the elements and factors that affect every decision; (5) the decisions individuals make during crisis situations
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will be discussed. One of the most widely known and important of the beliefs was the humours. It was believed that every living creature was composed of four elements‚ the humours. They were blood‚ phlegm‚ choler (or yellow bile)‚ and melancholy (or black bile). It was believed that the overall total combination of these four elements determined the person ’s characteristics. For example‚ a person with more blood than other humours was hot and wet in their nature‚ a person with more phlegm was
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talks about a pathologically shy‚ absentminded‚ stuffy‚ women-hating chemist. This man did make some discoveries about inflammable gas and proved water to be an oxide. The Element of Perfection Asimov talks about astronomers in the mid 1800’s‚ and how they made the spectroscope. Only then does he start to mention a element a french chemist belived to be new or maybe just a heavier from of nitrogen. Inert gases and there liquefaction points are then listed along when they when fisrt liquefied
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mostly space is: Rutherford A false statement concerning matter is: All matter contains mass. The true statement concerning the atomic nucleus is: It is made up of electrons only. The element The element has how many protons? 47 has how many neutrons? 146 Which statement is true? Isotopes of a given element have very similar chemical properties. The atomic number of an atom is equivalent to the number of: protons Rutherford coined the term used for the simplest positive charged particle and
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classroom. Henry Mosley recognized a pattern in the elements and arranged them so that they formed the Periodic Table we use today. Writing Directions Write an essay explaining how the Periodic Table is organized. Be sure to include the terms atomic number‚ atomic mass‚ families‚ and periods in the explanation 5. Objects composed of just one element can be bought from Wal-Mart‚ a hardware store‚ or even a pharmacy. Your friend thinks that elements can only be found in the earth or in your science
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Geology 101—Lesson 2 Assignment 1. What is meant by "hydrogen is the simplest of all elements"? Because hydrogen has an atomic number of only “1” which means it only has one proton in its nucleus and it is the only element with only one proton in its nucleus also has one electron 2. What must happen in order for an atom to lose its electrical neutrality? In order for an atom to lose its electrical neutrality the protons and electrons
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ANSWERS What is the term for the abbreviation for the name of a chemical compound that indicates the number of atoms of each element? c. chemical formula What is the term for matter having an indefinite composition and variable properties? c. heterogeneous mixture Which of the following laws states that a compound always contains the same elements in the same proportion by mass? d. law of definite composition Which of the following describes a substance in the liquid
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Shell = 2 x (3)2 = 18 p = 6 e = 6 n = 12 – 6 = 6 Group = have similar properties Period = do not have similar properties. = if you go from left to right the elements move from metals to semi metals to non-metals. Group = have similar properties Period = do not have similar properties. = if you go from left to right the elements move from metals to semi metals to non-metals. Valency: +1‚ +2‚ +3‚ +-4‚ -3‚ -2‚ -1‚ 0. Valency: +1‚ +2‚ +3‚ +-4‚ -3‚ -2‚ -1‚ 0. Trends & The Periodic Table
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