1. Writing Ionic Formulas Calcium Chloride Locate the metal on the periodic table and write the element symbol with its oxidation number. Ca +2

2. Writing Ionic Formulas Locate the nonmetal on the periodic table and write the element’s symbol with its oxidation number. Cl -1

3. Ca +2 Cl -1 Find the common factor between the two oxidation numbers. In this case, 2. Decide how many of each ion is needed to make the charge equal to the common factor. In this case, 1 calcium ion (+2) and 2 chlorine ions (-1 and –1 = -2). Compounds are neutral. Use this number of ions as the subscript for the element, and write the formula. In this case, Ca Cl 2.

4. Writing Ionic Formulas Part 2 Aluminum Oxide Locate the metal on the periodic table and write the element symbol with its oxidation number. Al +3

5. Writing Ionic Formulas Part 2 Locate the nonmetal on the periodic table and write the element’s symbol with its oxidation number. O -2

6. Al +3 O -2 Find the common factor between the two oxidation numbers. In this case, 6. Decide how many of each ion is needed to make the charge equal to the common factor. In this case, 2 aluminum ions (+3 and +3 = +6) and 3 oxygen ions (-2 and -2 and -2 = -6). Compounds are neutral. Use this number of ions as the subscript for the element, and write the formula. In this case, Al 2 O 3.

7. Try these examples on your own. Sodium and Oxygen Lithium and Sulfur Aluminum and Chlorine Potassium and Nitrogen Magnesium and Fluorine

8. Naming Ionic Compounds Write the name of the metal. Write the name of the nonmetal with the ending changed to –ide. Example: Nitrogen = nitrideSulfur = sulfide Oxygen = oxideChlorine = chloride Phosphorus = phosphideIodine = iodide Fluorine = fluorideBromine = bromide

9. Naming Ionic Compounds Al 2 S 3 Write the name of the metal. Aluminum Write the name of the nonmetal, changing the ending to –ide. Sulfide Name the compound. Aluminum Sulfide

10. Naming Ionic Compounds BaCl 2 Write the name of the metal. Barium Write the name of the nonmetal, changing the ending to –ide. Chloride Name the compound. Barium Chloride

11. Try these examples on your own. BeF Li 2 0 B 2 S 3 Mg 3 N 2 CaCl 2