1. IONIC COMPOUNDS

2. REVIEW OF ATOMIC STRUCTURE The structure of the atom Neutrons + Protons are in the nucleus Electrons in orbits around the nucleus Neutrons = Zero Charge Protons = Positive Charge Electrons = Negative Charge

3. Atoms in groups 1 – 13 (metals) will lose electrons in order to achieve a full outer shell They become cations (positive) Atoms in groups 15 – 17 (nonmetals) will gain electrons in order to achieve a full valence shell They become anions (negative) Combining Capacity: the number of electrons an atom needs to gain or lose to achieve a full outer shell The positive and negative ions attract to form an ionic bond IONIC COMPOUNDS – The Octet Rule

4. IONIC COMPOUNDS – Ionic Charges of the Elements +1 +2+3-3-2-1

5. IONIC COMPOUNDS – The Formation of an Ionic Bond

6. Ionic compounds are formed when a metal (M) is bonded to a nonmetal (N) In general: MNMN

7. MN

8. Rules Assign ionic charges to each atom Apply the criss-cross rule (ONLY the numbers travel, NOT the sign) Reduce the subscripts by dividing by the highest common factor Write your chemical formula IONIC COMPOUNDS – Writing Chemical Formulas

9. Example 1: sodium and chlorine IONIC COMPOUNDS – Writing Chemical Formulas NaCl +1 NaCl 1 1 Na

10. Example 2: calcium and chlorine IONIC COMPOUNDS – Writing Chemical Formulas CaCl +2 CaCl 1 2 Ca 2

11. Example 3: lithium and oxygen IONIC COMPOUNDS – Writing Chemical Formulas LiO +1-2 LiO 2 1 O 2

12. Example 4: magnesium and oxygen IONIC COMPOUNDS – Writing Chemical Formulas MgO +2-2 MgO 2 2 O Remember to find the HIGHEST COMMON FACTOR OMg 22

13. Rules… 1. Write the metal’s name first 2. Write the nonmetal’s name second (change the ending to “-ide”) For example: NaCl = sodium chloride IONIC COMPOUNDS - Naming

14. CaCl 2 Li 2 O MgO Calcium chloride Lithium oxide Magnesium oxide Chemical FormulaChemical Name

15. Some metals can have different combining capacities in different compounds For example: Copper (Cu) = 1, 2 Iron (Fe) = 2, 3 Lead (Pb) = 2, 4 Tin (Sn) = 2, 4 In these cases, the combining capacity must be specified using Roman Numerals IONIC COMPOUNDS – Multivalent Metals These numbers are written as Roman Numerals (i.e. I, II, III, IV, V)

16. IONIC COMPOUNDS – Multivalent Metals Iron(II) chlorideIron(III) chloride Iron has two combining capacities. Iron can have a +2 or +3 charge. FeCl 1 2 Fe 2 Cl +2 FeCl 1 3 FeCl +3 ClFe 3

17. “IONIC COMPOUNDS” Worksheet HOMEWORK