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Topic: Oxidation States and Lewis Dot Diagrams. Ionic bond is a bond between: Metal + Nonmetal. Metals: lose valence electrons form cation (+ ion) Nonmetals : gain electrons form anion (- ion). Metals are losers!. NOTICE: Full OCTECT. Na configuration 2-8-1
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Ionic bond is a bond between: Metal + Nonmetal • Metals: lose valence electrons • form cation (+ ion) • Nonmetals: gain electrons • form anion (- ion)
Metals are losers! NOTICE: Full OCTECT • Na configuration 2-8-1 • Ne configuration 2-8 • Na loses 1 electron → Na+1 • Na+1 configuration is 2-8! (Ne) • What will take the valence electron from Na??
Nonmetals are winners! NOTICE: Full OCTECT • Cl configuration 2-8-7 • Ar configuration 2-8-8 • Cl gains 1 electron → Cl-1 • Cl-1 has the configuration 2-8-8! (Ar) • What will donate an electron to Cl ??
The product (compound) formed doesn’t have same properties as the reactants.
IONIC BONDING • Ionic compounds are electrically neutral overall 1 Ca = +2 x 1 = +2 2 Cl = -1 x 2 = -2 2 K = +1 x 2 = +2 1 S = -2 x 1 = -2 2 Cr = +3 x 2 = +6 3 O = -2 x 3 = -6
Assigning Oxidation States • You can look at your periodic table. It’s listed in the topic right corner. • What do you do if there is more then one?!
What to do if more then 1 oxidation state • V2S5 • Nonmetal = top number • So S would be -2 • V2S5 -2 x 5 = -10 -2 +5 ____ x 2 = +10 +5 • Then determine the oxidation state of the metal that will give you the same number but positive
You try… +2 -2 • FeO Fe=____ O= ____ • Fe2O3 Fe=____ O= ____ -2 +3
Criss-Cross Method Mg+2 and Cl-1 Crisscross and Drop Mg1Cl2 but if subscript is 1, forget it! MgCl2 means 1 Mg+2 and 2 Cl-1
NOTE: The formula has to be in the simplest whole number ratio (this is called the empirical formular Be2O2 = BeO Al3N3 = AlN
Try a few formulas: CaCl2 • Ca+2 + Cl-1 • Na+1 + O-2 • Cs+1 + S-2 • Al+3 + Cl-1 • Al+3 + Se-2 • Mg+2 + F-1 • Ca+2 + S-2 Na2O Cs2S AlCl3 Al2Se3 MgF2 CaS