1. Ionic bonds and Compounds

2. TYPES OF BONDS IONIC BONDS COVALENT BONDS transfer of electrons between a Cation and an Anion resulting bond is neutral sharing of electrons between two or more nonmetals Two types- polar or non-polar Example NaCl MgSO 4 Example H 2 O Cl 2

3. ionic compounds consist of a combination of cations and an anions the formula is always the same as the empirical formula the sum of the charges on the cation(s) and anion(s) in each formula unit must equal zero The ionic compound NaCl

4. Most ionic compounds form Crystalline Structure Formulas for ionic compounds are generally empirical formulas. Ionic compounds are electronically neutral.

5. Naming Ions and Ionic Compounds To name ionic compounds: 1) Name the cation  omit the word ion  use a Roman numeral if the cation can have more than one charge  If the element has latin name use classical method 2) Name the anion  omit the word ion Examples: NaCN sodium cyanide FeCl 2 iron(II) chlorideFerrous Chloride FeCl 3 iron(III) chlorideFerric Chloride

6. Al 3+ O 2– Al 2 O 3 In order for ionic compounds to be electronically neutral, the sum of the charges on the cation and anion in each formula must be zero. Aluminum oxide: Sum of charges:2(+3) + 3(–2) = 0 Formulas of Ionic Compounds

8. Calcium phosphate: 5.7 Ca 2+ PO 4 3– Ca 3 (PO 4 ) 2 Sum of charges:3(+2) + 2(–3) = 0 Ionic compounds with polyatomic ions

9. Hydrates A hydrate is an ionic compound that has a specific number of water molecules within its solid structure. For example, in its normal state, copper(II) sulfate has five water molecules associated with it. Systematic name: copper(II) sulfate pentahydrate Formula: Cu(SO) 4 ∙ 5H 2 O Some other hydrates are BaCl 2 ∙ 2H 2 O Can you name them??? LiCl ∙ H 2 O MgSO 4 ∙ 7H 2 O Sr(NO 3 ) 2 ∙ 4H 2 O

10. Hydrates When the water molecules are driven off by heating, the resulting compound, Cu(SO) 4, is sometimes called anhydrous copper(II) sulfate. Anhydrous means the compound no longer has water molecules associated with it.

11. Worked Example 5.9 Strategy Begin by identifying the cation and anion in each compound, and then combine the names for each, eliminating the word ion. Name the following ionic compounds: (a) Fe 2 (SO 4 ) 3, (b) Al(OH) 3, and (c) Hg 2 O. Solution (a) Fe 2 (SO 4 ) 3 is iron(III) sulfate. (b) Al(OH) 3 is aluminum hydroxide. (c) Hg 2 O is mercury(I) oxide. Think About It Be careful not to confuse the subscript in the formula with the charge in the metal ion. In part (a), for example, the subscript on Fe is 2, but this is an iron(III) compound.

12. Formula of Ionic Compounds Al 2 O 3 2 x +3 = +63 x -2 = -6 Al 3+ O 2- CaBr 2 1 x +2 = +22 x -1 = -2 Ca 2+ Br - Na 2 CO 3 1 x +2 = +21 x -2 = -2 Na + CO 3 2-

13. Recognizing Ionic Compounds A compound is ionic if it contains a metal from group 1 Or group 2 or one of the polyatomic ions. Binary metal Oxides and sulfides also have ionic character

14. Chemical Nomenclature Ionic Compounds –often a metal + nonmetal –anion (nonmetal), add “ide” to element name BaCl 2 barium chloride K2OK2O potassium oxide Mg(OH) 2 magnesium hydroxide KNO 3 potassium nitrate

15. Cations of Variable Charge Transition metals such as copper may form cations Of different charge. This is represented by placing a Roman numeral after the transition metal in Parentheses after the name of the metal. CuO Copper(II) oxide Cu 2 O Copper(I) oxide

16. Transition metal ionic compounds –indicate charge on metal with Roman numerals FeCl 2 2 Cl - -2 so Fe is +2 iron(II) chloride FeCl 3 3 Cl - -3 so Fe is +3 iron(III) chloride Cr 2 S 3 3 S -2 -6 so Cr is +3 (6/2)chromium(III) sulfide

17. Hydrates A hydrate is an ionic compound that has water molecules Incorporated into their solid structures Writing the formula: name of ionic compound-# H 2 O Copper(II)sulfate. pentahydrate Olmsted Williams