Chem 30A Ch.1-4: Condensed Chang’s Class Notes Chapter 1 Valence electrons octet rule exceptions P and S can have 10 or 12 valence e- B and Al (Group 3) can have 6 valence e- electronegativity- how much an atom wants e- < 0.5 = nonpolar‚ covalent (i.e. H2) 0.5 - 1.9 = polar covalent direction of polarity (using arrow and delta symbol) overall dipole > 1.9 = ionic formation of ions fish-hook arrow Lewis structure formal charge Functional Groups Molecular Shape VSEPR (Valence Shell
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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education *1144188971* COMBINED SCIENCE Paper 2 (Core) 0653/21 October/November 2010 1 hour 15 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your Centre number‚ candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use a soft pencil for any diagrams‚ graphs‚ tables or rough working
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electricity‚ life as we know it would be impossible. Electrostatic forces - both attractive and repulsive in nature - hold the world of atoms and molecules together in perfect balance. Without this electric force‚ material things would not exist. Atoms as the building blocks of matter depend upon these forces. And material objects‚ including us Earthlings‚ are made of atoms and the acts of standing and walking‚ touching and feeling‚ smelling and tasting‚ and even thinking is the result of electrical phenomenon
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FREE SPACE OPTICS NEXT GENERATION COMMUNICATION PRESENTED BY V.LAXMANA VENKATA KUMAR 09PA1A04B6 ABSTRACT: FSO may sound new and experimental but in fact it predates optical fiber and has its roots in wartime efforts to develop secure communication systems that did not require
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ketones both contain the carbonyl group – a group in which a carbon atom has a double bond to oxygen. The carbonyl group in aldehydes is bonded to at least one hydrogen atom‚ and in ketones it is bonded to two carbon atoms. The general formula for an aldehyde is And the general formula for a ketone is Aldehydes and ketones have a trigonal planar arrangement of groups around the carbonyl carbon atom. The carbon atom is sp2 hybridized‚ On the other hand‚ the acidic compounds are
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Finalized Notes Cells are small membrane bound units filled with concentrated aqueous solution of chemicals and given the ability of reproducing itself by dividing. Thus for this purpose the cells are the fundamental unit of life. If cells are modified to specific specialization they cause the cell to lose its ability to reproduce‚ as a result they end up depending on other cells for the basic needs. In all living things genes are stored in the DNA molecule‚ encoded in the same chemical code
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reactions take place. It gives accurate predictions about the operation of lasers and microchips‚ the stability of DNA and how alpha particles tunnel out of the nucleus." (Barlett) What is being study is the smallest part of our existence‚ the atom. " The problems of language her are really serious. We wish to speak in some way about the structure of the atom. But we can speak about atoms in ordinary language." (Durham) Quantum theory develops equations to explain the very abstract questions
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and compounds. a. Elements consist of a single kind of atom; They have unique‚ fixed properties; They cannot be separated into simpler unique substances. Compounds consist of two or more kinds of atoms bonded together; They have unique‚ fixed properties not related to the properties of the components. The can be separated into elements using chemical means such as electrolysis. Mixtures consist of two of more kinds of atoms or molecules mixed together‚ but not bonded. They have
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AS Chemistry Revision-Chemistry for Life 1. Avagadro constant‚ 6.02 x 10²³ number of particles in 1 mole of a substance 2. Empirical formula-simplest ratio of atoms of each element in a compound 3. 4. Model of an atom Particle Mass on relative atomic scale Charge Proton 1 1+ Neutron 1 0 Electron Very small (0.00055) 1- 5. Radioactive isotopes Radiation What is it? Relative charge How does the nucleus change? Stopped by? Deflection in electric field? Alpha α Helium nuclei ⁴₂He +2 2 fewer
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(i) Write the names of the compounds represented by the following formulae: a) Na 2S b) KNO 3 (ii) Write the chemical formulae of : Aluminum Chloride Magnesium oxide (iii) Find out the mass of 12.044 × 10 23 atoms of magnesium (Given at mass of Mg = 24.0µ) 3 21. A stone is dropped from the edge of the roof. a) How long does it take to fall 4.9 m? b) How fast does it move at the end of the fall? c)
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