Chapter 3 PERIODIC TABLE AND PERIODICITY OF PROPERTIES Q.1 What are the contributions of Dobereiner‚ Newland‚ Luthar Meyer and Mendeleef in the present shape of long form periodic table ? Dobereiner’s Triads : In 1829‚ a German scientist‚ John Dobereiner classified specific elements into groups in order of increasing atomic masses. Each group has three elements. He named these groups as triads.He noticed that the atomic mass of the middle elements was found to be approximately equal to the
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the entire semesters work. Chemistry 1. Label the following on a periodic table: a) Alkali metals b) Alkaline earth metals c) Halogens d) Noble gases 2. Indicate the metals‚ non-metals and metalloids. -38100431803. Show the trends for reactivity and atomic radius. 4. Which of the following elements has the largest atomic radius? Why? a) fluorine b) oxygen c) nitrogen d) calcium Calcium has the largest atomic radius as it has 3 rings of electrons‚ while the rest of the
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Chemistry Summary The particle theory: 1. Matter is made of tiny particles 2. Particles of matter are in constant motion 3. Particles of matter are held together by very strong electric forces 4. There are empty spaces between the particles of matter that are very large compared to the particles themselves. 5. Each substance has unique particles that are different from the particles of other substances 6. Temperature affects the speed of the particles. The
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What do you understand by the term “Lancefield groups”? History In the early 1930’s Rebecca Lancefield recognized the importance of serological tests for the identification of organisms. The system is based on specific antibody agglutination reactions with cell wall carbohydrate antigens (C polysaccharides) extracted from the streptococci. Lancefield also showed that further sub division of group A into specific serological types was possible using type-specific M (protein) antigens. The groups
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Chemistry Research Task The Periodic Table of Elements The Periodic Table of Elements is used as a way of displaying all the known chemical elements; it is accepted and used all over the world. The periodic table’s layout is very well structured; it consists of vertical rows called groups and horizontal rows called periods. It is one of the most important resources in chemistry and the key to discovering new elements. The beauty of the Periodic Table is that a lot of information about any
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Journal of Materials Science and Engineering B 1 (2011) 86-89 Formerly part of Journal of Materials Science and Engineering‚ ISSN 1934-8959 Conversion of Plastic Wastes into Fuels Antony Raja and Advaith Murali Department of Chemical Engineering‚ Sri Venkateswara College of Engineering‚ Sriperumbudur 602105‚ India Received: October 23‚ 2010 / Accepted: November 10‚ 2010 / Published: June 10‚ 2011. Abstract: Plastics have woven their way into our daily lives and now pose a tremendous threat
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aeration time‚ the formation of the iron oxy-hydroxide species and also coating the surface with these species increase. Then‚ however‚ because of the coverage of most of the pyrite surface by these species‚ a significant decrease in the surface reactivity with oxygen occurs. In other words‚ with further increase in aeration time‚ the pyrite surface is
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8.2 Chemical Earth 8.2.1 The living and non-living components of the Earth contain mixtures * Construct word and balanced formulae equations of chemical reactions as they are encountered Combustion reaction (burning) element + oxygen → oxide e.g. 4Na (S) + O2 (g) → Na2O (s) Reaction with hydrogen element + hydrogen → hydride e.g. Ca (s) + H2 (g) → CaH2 (s) Reaction between an oxide and water metallic oxide + water → hydroxide * metallic oxide is also known as “basic oxide” e.g
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IB Chemistry Summary- By Paul Li & Silvia Riggioni TABLE OF CONTENTS Table of Contents............................................................................................................................................................ 1 Atomic Theory................................................................................................................................................................ 3 The Electromagnetic Spectrum.............................................
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Traditional way of synthesizing sensitive rhodamine starts with rhodamine B‚ amino compound‚ and some alkali additive in the presence of weak base. However‚ for RH-PY‚ the stearic hindrance of pyrene slows the reactivity‚ and the reaction does not go to completion. Therefore‚ the reaction procedure was modified as follows. First‚ HATU and DIPEA were used to activate the carboxyl group of rhodamine B‚ then the activated rhodamine B was reacted with 1-aminopyrene. By introducing this method‚ the reaction
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