Oc o oo c all atoms are surrounded by 8e octet formal

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Unformatted text preview: wis structure for CO2 also satisfies the octet rule! Which one is correct? OC O OO C All atoms are surrounded by 8e → octet! Formal Formal Charges Formal charge: the charge assigned to each atom charge in a Lewis structure if all atoms had the same Lewis all electronegativity. Formal charge of an atom = number number of its valence valence electrons electrons in isolated atom – sum of all the electrons electrons assigned to to the atom in Lewis structure 1) Assign all non-bonding electrons all nonaround an atom to the atom. 2) Assign half of the bonding electrons half the to each atom joined by the bond . Formal Formal Charges Best Lewis structure : the With the lowest possible formal charges on all atoms, AND/OR With negative formal charge on the atom with higher negative with electronegativity. OC O OO C Write the Lewis structure of CH2O: 0 H -1 C +1 O 0 H 0H 0H 0 C 0 O Electron Electron Affinity Ionization energy EN = k ( IE − EA) 8.101 Lattice Energy (Electrostatic Attraction) Lattice energy (E): much depends on the charges of charges ions, the sizes of ions and their arrangement in solid sizes arrangement Q+ : the charge on the cation Q+ ⋅ Q− E=k r Q- : the charge on the anion r : the distance between the ions Compound Lattice energy (E) lattice energy MgF2 MgO 2957 LiF LiCl 1036 853 3938 Q= +2,-1 Q= +2,-2 increases as Q increase increases as r decreases r(F) < r(Cl) Dipo...
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This document was uploaded on 02/26/2014.

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