1. Activity Directions: Use the worksheet to guide you as you create the formulas. You will be matching the blue and yellow elements according to their valance electrons. Each element has a charge written on it. Pay attention to the charges as you go through the activity. Do not move on to a new formula until you are directed.

3. Rules for writing the name of ionic formulas: 1. Write the name of the metal first. 2. Change the ending of the nonmetal to –ide. Examples: Formula Name A. Li2O B. KCl Potassium Chloride Lithium Oxide

4. 1.The total charge of an ionic formula must be zero 2.The sum of the positive charges must equal the sum of the negative charges. Rules for writing the Ionic formula from the name:

5. NaCl What is the charge of the sodium ion? Na is in group 1 Na has 1 valence electron Na is a metal so it loses that electron The charge of Na will be +1 Na +1

6. What is the charge of the Chlorine ion? Cl is in group 17 Cl has 7 valence electrons Cl is a nonmetal so it gains 1 electron The charge of Cl will be -1 Cl -1

7. Na +1 Cl -1 Add the charges together: +1 + (-1) = 0 The name of this formula is Sodium chloride

8. BeS What is the charge of the beryllium ion? Be is in group 2 Be has 2 valence electrons Be is a metal so it loses 2 electrons The charge of Be is +2 Be +2

9. What is the charge of the sulfur ion? S is in group 16 S has 6 valence electrons S is a nonmetal so it gains 2 electrons The charge of S will be -2 S -2

10. Be +2 S -2 Add the charges together: +2 + (-2) = 0 The name of this formula is Beryllium sulfide

11. K3PK3P What is the charge of the potassium ion? K is in group 1 K has 1 valance electron K is a metal so it loses 1 electron The charge of one ion of K is +1 There are 3 ions of K in the formula K +1

12. What is the charge of the phosphorus ion? P is in group 5 P has 5 valence electrons P is a nonmetal so it gains 3 electrons P has a charge of -3 P -3

13. K +1 Add the charges together: +1 +1 +1 + (-3)= 0 The name of this formula is Potassium Phosphide K +1 P -3

14. Writing Ionic Formulas In order to determine the formula, you must determine the charge of each ion in the formula. Formula Name Magnesium chloride What two elements are involved in this ionic formula? Magnesium and Chlorine

15. One ion of Mg has +2 charge Mg +2 One ion of Cl has a -1 charge Cl -1 +2+(-1) = +1 The charges do not equal zero, therefore to make this formula, there must be additional ions in this formula.

16. Mg +2 Cl -1 Magnesium still has one place to bond. It has an unused valence electron. Magnesium needs 2 ions of Chlorine to use up all of the valence electrons and make the sum of the charges equal zero. Mg +2 Cl -1 Cl -1 +2 +(-1)+(-1)= 0

17. Magnesium Chloride MgCl 2 There is one ion of Magnesium and two ions of Chlorine in Magnesium Chloride.

18. Writing Ionic Formulas In order to determine the formula, you must determine the charge of each ion in the formula. Formula Name MgCl 2 Magnesium chloride What two elements are involved in this ionic formula? Magnesium and Chlorine

19. Example: Formula Name Calcium bromide Calcium and Bromine Ca +2 CaBr 2 Br -1 +2 + (-1) +(-1)= 0