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Ionic Compounds (p. 176 – 180, 203 – 211). Ionic Compounds. M ost of the rocks and minerals that make up Earth’s crust consist of positive and negative ions held together by ionic bonding. An ionic compound is composed of positive and negative ions that are
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Ionic Compounds • Most of the rocks and minerals that make up Earth’s crust consist of positive and negative ions held together by ionic bonding. • An ionic compound is composed of positive and negative ions that are combined so that the numbers of positive and negative charges are equal. • Most ionic compounds exist as crystalline solids
Ionic Compounds • The chemical formula of an ionic compound merely represents the simplest ratio of the compound’s combined ions that gives electrical neutrality. • A formula unit is the simplest collection of atoms from which an ionic compound’s formula can be established.
Dot Diagrams • show transfer of e-
Dot Diagrams show transfer of e-
Electron Dots For Anions P P-3
Ionic Bonding Ca+2 Ca+2 P -3 Ca+2 P -3
Ionic Bonding Ca3P2 Calcium phosphide
Ionic Nomenclature Common Ion Charges 1+ 0 2+ 3+ NA 3- 2- 1- varies
Binary Ionic compounds • Made of two different elements that have formed ions • End in -ide
Monatomic ions – p. 205 • Ions formed from a single atom • Metals from positive monatomic ions • Nonmetals form negative monatomic ions ( nonmetal ions end in –ide, ex. Chlorine becomes the chloride ion)
Variable oxidation #’s • Some elements have more than one oxidation number. • Groups 3 - 12, tin, lead. The stock system of nomenclature uses roman numerals to indicate the oxidation number. • (p.205)
Al 3+ O 2- Al 2 O 3 (6 +) + (6-) = 0 Formula is Al2O3
Write the formulas for these • Lithium sulfide • tin (II) oxide • tin (IV) oxide • Magnesium fluoride • Silver chloride • Iron (III) phosphide • Iron (III) sulfide • Potassium iodide
Write the formulas for these • Sodium sulfide • Aluminum sulfide • Aluminum nitride • Copper (II) bromide • Iron (II) oxide • Lead (II) chloride • Mercury (II) sulfide
Compounds with polyatomic ions • Review the list on page 210 • All are negative except the ammonium ion • Most are oxyanions (contain oxygen) • When more than one polyatomic ion is in a compound, parentheses must be placed around the polyatomic ion.
Compounds with polyatomic ions • Copper (II) sulfate • calcium nitrate • barium nitrate • Ammonium chloride • ammonium sulfide • Lithium nitrate • Sodium carbonate • Potassium perchlorate
Naming Binary Ionic Compounds • Write the name of the cation first • Write the root of the anion, end in -ide • NaCl = sodium chloride • MgBr2 = magnesium bromide • KI = potassium iodide • BaO = barium oxide
Naming Binary Ionic Compounds • The problem comes with the variable transition metals. • You must determine the roman numeral.
CuO CoCl3 Cu2S Fe2O3 SnCl2 CrN Sc3P2 PbO PbO2
Ionic Compounds with polyatomic ions the ending of the polyatomic ion doesn’t change NaNO3 CaSO4 CuSO3 (NH4)2O LiCN Fe(OH)3
(NH4)2CO3 NiPO4 FeCrO4 Pb3(PO4)2 • See Sample Problems 7-1,7-2,7-3 (p.207,209,211) • h.w. p. 236 # 27, 41,Handout p.2