Dr. John Andraos‚ http://www.careerchem.com/NAMED/Elements-Discoverers.pdf 1 NAMES OF SCIENTISTS ASSOCIATED WITH DISCOVERIES OF ELEMENTS OF PERIODIC TABLE © Dr. John Andraos 2002 - 2005 Department of Chemistry‚ York University 4700 Keele Street‚ Toronto‚ ONTARIO M3J 1P3‚ CANADA For suggestions‚ corrections‚ additional information‚ and comments please send e-mails to jandraos@yorku.ca http://www.chem.yorku.ca/NAMED/ Z‚ Element Symbol Discoverer Dates Nationality Place
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Atoms of a given element which have the same number of protons but different numbers of neutrons are called isotopes. Thus‚ isotopes have the same position in the periodic table‚ the same chemical properties and the same atomic charge. The simplest example of an atom with different isotopes is hydrogen. The three isotopes of hydrogen are shown here: The increasing number of neutrons in the nucleus of the hydrogen atom adds mass to the atom and thus each isotope of a given element has a different
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and Its Parent Elements Hypothesis The hypothesis of this experiment is magnesium oxide can be synthesized by combining (burning) the magnesium with oxygen. The chemical and physical properties of each element (magnesium‚ oxygen‚ and magnesium oxide) might be different‚ from the state‚ color‚ electrical conductivity‚ and pH. Aim This experiment was performed to synthesize magnesium oxide by direct combination of magnesium and oxygen and to compare the properties of the elements (magnesium and
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But do you recall munching some molybdenum or snacking on selenium? Some 60 chemical elements are found in the body‚ but what all of them are doing there is still unknown. Roughly 96 percent of the mass of the human body is made up of just four elements: oxygen‚ carbon‚ hydrogen and nitrogen‚ with a lot of that in the form of water. The remaining 4 percent is a sparse sampling of the periodic table of elements. Some of the more prominent representatives are called macro nutrients‚ whereas those
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MATTER AND CHANGE Name _____________________________________ PRACTICE PROBLEMS Period _________________ Date ______________ SECTION 2.1 MATTER 1. Which of the following is not a physical change? a. dissolving sugar in water b. burning gasoline in an engine c. evaporating sea water to obtain salt d. slicing a piece of bread 2. Which of the following is not a property of a gas? a. has a definite shape b. has no definite volume c. assumes the shape of
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would look for how this cell or organism would execute homeostasis‚ as well as look for DNA. These are all properties that all living things share. 2. What happens if an atom of an element gains or loses electrons? What happens if an atom of an element gains or loses neutrons? What happens if an atom of an element gains or loses protons? Atoms in which the number of
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protons and electrons than tin? 6. Is mercury a heavier element than tin? 7. Does potassium have more electrons than neon? 8. Does hydrogen have more electrons than Uranium? 9. Which has more protons‚ sulfur or iodine? 10. Which has more protons‚ iodine or silver? 11. In the boxes below make Bohr models for each of the elements. a. Determine how many electrons‚ protons‚ and neutrons there are in each atom. b. Draw a Bohr model of each element using the number of electrons‚ protons‚ and neutrons c
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Inventory Control Automated Office System David Pierce Individual Project IS316 - Systems Analysis and Design Professor: Erlan Burk Park University Fall II 2010 Table of Contents System Description 2-3 Functional Description 4-5 Data Dictionary 6-8 Context Level Diagram and Child Diagram 9-12 System Input‚ Output Forms‚ and Interfaces 13-14 Testing‚ Maintenance and Auditing 15 System
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Boron On the Periodic Table The chosen element was “Boron”. Its atomic number on the periodic table is 5. It has 5 protons/electrons and 6 neutrons. The scientific symbol for Boron is “B”. It is not a gas element; it is in between a metal and a non-metal‚ which they would call a metalloid or a semimetal. At room temperature‚ this element is a solid. The density is 2.34 g/cm3. When it is at room temperature‚ it is a poor electric conductor‚ but when it is at high temperatures‚ it is a good
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Lanthanide family. Neodymium is a chemical element with the symbol Nd‚ the atomic number 60‚ and a soft‚ bright‚ silvery white metal. It was first identified in 1885‚ in Vienna‚ by Austrian scientist Carl Auer von Welsbach. Neodymium was discovered in ‘didymium’ a substance incorrectly identified by Carl Mosander in 1841. In 1869‚ ‘didymium’ had the symbol Di in Mendeleev’s first periodic table in 1869. Many people‚ such as Bohuslav Brauner‚ tried to identify the element
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