Solids • metals (good electrical/heat conductors) • semiconductors • insulators (poor electrical/heat conductors) Bonding in solids: Ionic solids Ionic solid crystals (e.g. NaCl) are held together by the Coulomb attractive interaction between ions with opposite sign (ionic bonding) e2 b U = −αk + m r r (α = 1.7476 for Na +Cl − ) (m ~ 10) k = 1 / 4πε 0 Madelung constant Ionic cohesive energy: 11 U0 = min U (r ) = −αk 1 − m r0 mb r0 = αk 1 m −1
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complications. The present article discusses various issues associated with biological corrosion of different kinds of implants used as cardio stents‚ orthopedic and dental implants. As the materials used for these implants are manifold starting from metallic materials such as stainless steel (SS)‚ cobalt chromium‚ titanium and its alloys‚ bioceramics‚ composites and polymers are in constant contact with the aggressive body fluid‚ they often fail and finally fracture due to corrosion. The corrosion
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1.0 INTRODUCTION Flame photometry‚ also referred to as ’flame atomic emission spectrometry ’ is a quick‚ economical and simple way of detecting traces of metal ions‚ primarily Sodium‚ Potassium‚ Lithium‚ Calcium‚ and Barium‚ in a concentrated solution. The process is an extension of the principles used in a flame test‚ with the main differences having more precision in the results‚ and the use of more advanced technology. This report focuses on the theory‚ applications‚ limitations and analysis
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it emits the absorbed energy in the form of light. A platinum or nichrome wire was dipped into aconcentrated HCL and was heated to clean it. The wire was dipped into different salt solutionsand heated in order to determine the metallic ion’s color and wavelength. Metal ions emitting aviolet-colored flame has the largest amount of energy while those that emit red-colored flamehave the least amount of energy. Introduction An atom is the smallest particle of an element‚ which can exist and still
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Chemical bond From Wikipedia‚ the free encyclopedia Jump to: navigation‚ search A chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electrostatic force of attraction between opposite charges‚ either between electrons and nuclei‚ or as the result of a dipole attraction. The strength of chemical bonds varies considerably; there are "strong bonds" such as covalent or ionic bonds and "weak bonds"
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Purpose: To determine the colors of the Atomic Emission Spectra of several metallic ions. Materials: Safety glasses 10 test tubes Test tube rack Paper Pencil 50 mL beaker Bunsen burner Nichrome wire Barium Nitrate Copper Nitrate Strontium Nitrate Lithium Nitrate Potassium Nitrate Sodium Chloride Calcium Nitrate Unknown solutions A‚B‚ & C Hydrochloric Acid Wash bottle (with distilled water) Procedure: 1. Label the test tubes with the names of the solutions and unknowns. 2. Place
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between non-metal atoms. 3. What is a chemical bond? Discuss the differences between an ionic bond and a covalent bond. Any of several forces‚ especially the ionic bond‚ covalent bond‚ and metallic bond‚ by which atoms or ions are bound in a molecule or crystal. Ionic bonds are chemical bonds between two ions with opposite charges‚ characteristic of salts. Covalent bonds are chemical bond formed by the sharing of one or more electrons‚ especially pairs of electrons‚ between atoms. 4. What are
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Study Guide GEOL 1500 test #1 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) What are the basic differences between the disciplines of physical and historical geology?|1)| A) physical geology is the study of fossils and sequences of rock strata; historical geology is the study of how rocks and minerals were used in the past B) physical geology involves the study of rock strata‚ fossils‚ and deposition in relation
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Edexel IGCSE Chemistry Revision Notes IGCSE Chemistry Triple Award Revision Guide Topic Introduction to chemistry Atomic Structure Structure and Bonding – Ionic Bonding Structure and Bonding – Covalent and Metallic Bonding Organic Chemistry - Alkanes Organic Chemistry – Alkenes / Addition Polymerisation Organic Chemistry – Alcohols / Condensation Polymerisation Calculations Periodic Table Reactivity Series and Metal Extraction Electrolysis Energetics Acids‚ Bases‚ Salts and Neutralisation
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bonding Ionic bonds are chemical bonds formed through an electrostatic attraction between two oppositely charged ions. Ionic bonds are formed between an metal and a non-metal. The metal loses an electron or electrons form its highest energy level becoming a positively charged Ion and the non-metal gains an electron or electrons in its highest energy level‚ becoming a negatively charged Ion. Covalent bonds are strong bonds between two non-metal atoms. A covalent bond forms when two non-metal atoms
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