1. Do Now How many valence electrons does a sodium atom have? Hint: find this based on sodium’s location on the periodic table. How many valence electrons does a nitrogen atom have? How many valence electrons does Na 3 N have? Hint: add three times your answer to question 1 to your answer to question 2.

2. Aim Do we have any other tricks for solving chemical structures?

3. Introduction Draw a Lewis structure of Na 3 N AND a Lewis structure of AlF 3 in the space provided. In Na 3 N, nitrogen is the “central atom.” In AlF 3, aluminum is the “central atom.” Based on your structures in question 1, what is meant by central atom?

4. Introduction In BCl 3, boron is the central atom. You can tell which atom is the central atom by looking at the formula. What is true about the number of the central atom in the three salts you have seen? Identify the central atom in each of the following molecules: A)K 2 OB) GaH 3 C) FrI 3

5. New Idea: Everyone gets a number! Al 2 O 3 Sr 3 P 2

6. Ion Medley! Fr 2 S Ra 3 N 2 LiBr SrCl 2 In 2 P 3 Challenge: NaKCsP

7. The Last Trick: Multiple Bonds Q: Do we have a double or triple bond? A: If the number of hydrogen + is twice the number of or less Example:

8. Try it out! Find a structure for C 4 H 8 (bonus points for two): Find a structure for C 2 H 4 O (bonus points for two): Challenge  Find two structures for C 4 H 6 (there are three):