Lesson 1: Valence Electrons, Oxidation #, Dot Diagrams

Chemical Bonding and Chemical Interactions

1. Physical Science Date: July 19, 2014 Objective: I can predict the oxidation number and number of valence electrons for an element as well as draw Lewis dot diagrams . To Do: Complete Catalyst (5 minutes) Have binder ready & periodic table out

2. Catalyst: Review Subatomic Particle Charge Location Size proton electron neutron positive negative neutral Inside nucleus Inside nucleus outside nucleus 1 amu 1 amu 1/2000 amu

3. Catalyst: Review Compare a period to a group on the periodic table. A period is a row on the periodic table There are 7 periods A group is a vertical column There are 8 representative groups Both contain elements and provide useful information about atoms

4. Catalyst: Review Periods Groups

5. Catalyst: Review What can the period or row tell you when drawing Bohr models? A period or row tells you how many rings or shells to draw on a Bohr model.

6. Catalyst: Review Sodium Carbon Remember: 1 st ring: 2 e- 2 nd ring: 8 e- 3 rd ring: 18 e-

7. Today’s Objective Objective: I can predict the oxidation number and number of valence electrons for an element as well as draw Lewis dot diagrams .

8. Vocabulary Valence electron: An electron on the outermost energy level in an atom 1 valence e- 4 valence e-

9. Valence electrons Atoms in the same family have the same # of valence electrons Elements in the same family have similar properties

10. Valence electrons 1 2 3 4 5 6 7 8 Label your periodic tables as shown here:

11. popcorn We will play popcorn around the classroom We will ask questions about valence electrons For example, “How many valence electrons does Nitrogen have?” If you answer correctly, you may choose the next student to ask a question to

12. Vocabulary Oxidation Number: Refers to the number of electrons lost or gained during chemical bonding When metals and nonmetals form compounds, they lose or gain valence electrons

13. Vocabulary Ionic Bond : A bond between a metal and a nonmetal Ion : An atom with a positive or negative charge

14. Ions A n ion is an atom that has a positive or negative electric charge Represented by the plus or minus sign Na + Plus sign tells me that this sodium atom gave an electron away

15. Oxidation # + 1 + 2 + 3 +- 4 - 3 - 2 - 1 Label your periodic tables as shown here:

16. Oxidation # Metals have a positive charge because they lose electrons Nonmetals have a negative charge because they gain electrons

17. Lewis dot diagrams Bohr diagrams help us see electron configurations for atoms Bohr diagrams help us understand reactivity Lewis dot diagrams show valence electrons only

18. Write the chemical symbol Find the # of valence electrons (group #) Draw the valence electrons (cross method) Drawing Electron dot diagrams Valence electrons = 7 Cl

19. Examples:

20. Practice Using your dry erase board, draw dot diagrams for the element I call out When I say to, hold up your dry erase board Work independently

21. Activity Complete the Mix & Match Activity with your table partner When finished, raise your hand and I will check your work You have 25 minutes to complete correctly Pick-up the Periodic Table Challenge when finished

22. Exit ticket Complete the Exit Ticket You may use your periodic table Keep eyes on your own paper 10 minutes