CHEM 1061 1nd Edition Lecture 25 Outline of Last Lecture I Monoatomic Ions II Pseudo Noble Gas Configurations III Transition Elements IV Trends in Atomic Size V Isoelectric Ions Outline of Current Lecture II Bonding III Ionic Bonding IV Born Haber Cycle a examples Current Lecture Bonding Bonding is the favorable interaction that stabilizes or lowers the energy 1 2 3 4 Ionic bonding Covalent Bonding Electronegativity Metallic Bonding Ionic Bonding Usually ionic bonding is between a metal and a nonmetal ex Na Cl Ne 3s 1 Ne 3s 2 3p 5 Na has one valence electron Cl has seven valence electrons These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Lewis Dot Symbol of dots group of valence electrons Electron transfer happens Na Cl Ne Ar NaCl Octet rule outer shell of 8 electrons same as noble gas configuration full shell Lattice Energy What holds ionic compounds together Represented by Holattice 1mol solid ionic compound to start NaCl s Na g Cl g Separated ions in gaseous state H for Hlattice positive it takes a lot of energy to pull a solid apart into ions endothermic put in energy Born Haber Cycle An application of Hess s law EXAMPLE Born Haber cycle for formation of LiF What is the Hlattice Target Equation Li S F2 g LiF s H f 617 KJ Any of the following equations can be set equal to the heat of formation equation 1 Li s Li g H sublimation 161 KJ 2 1 2F 2 g F g H bond energy 79 5 KJ 3 Li g Li g eH IE1 520 KJ 4 F g e F g H EA1 328 KJ 5 LiF s Li g F g H lattice DO NOT add target equation into identifying equations once you know your target leave it alone Flip 5 because LiF is a product in the target Change the H to be negative Reactants Li s 1 2F 2 g Li g F g Li g F g eProducts Li g F g Li g e F g LiF s Only cancel out identical things Caution on the anions and cations Li s F 2 g LiF s matches target Add up H 161 KJ 79 5 KJ 520 KJ 328 KJ Hlattice 617 KJ 617 KJ 432 5 KJ Hlattice 1050 KJ Hlattice 1050 KJ Postive because the reaction is ENDOTHERMIC
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