1. VSEPR Theory and Molecular Shapes Lab

2. Make sense of problem and persevere in solving them
Objective
Today I will be able to:
Draw Lewis Structures to represent the valance electrons of atoms
Represent the formation of ionic and covalent compounds using Lewis Structures
Predict the molecular shape of a molecule using the VSEPR theory
Evaluation/ Assessment
Informal assessment – Listening to group interactions as they complete the illustrating ionic and covalent compounds practice and the molecular shapes lab.
Formal Assessment – Analyzing student responses to the exit ticket and the practice worksheets.
Common Core Connection
Make sense of problem and persevere in solving them
Reason abstractly and quantitatively
Use appropriate tools strategically
Look for and make use of structure

3. Lesson Sequence Warm – Up Explain: Writing an Abstract
Explain: VSEPR Theory (Day 1)
Explore and elaborate: Molecular Shapes Lab (Day 1 & 2)
Informal Assessment
Evaluate: Exit Ticket
Formal assessment

4. Warm - Up
How do I determine the number of valence electrons an atom has?
How many valence electrons does the following elements have:
1) Boron
2) Nitrogen
3)Barium

5. Objective Today I will be able to:
Draw Lewis Structures to represent the valence electrons of atoms
Represent the formation of ionic and covalent compounds using Lewis Structures
Predict the molecular shape of a molecule using the VSEPR theory

6. Homework STEM Fair Conclusion Re-Dos due Monday the 15th
Abstract due Friday Dec 19th

7. Agenda Warm-Up Writing an Abstract VSEPR Notes (Day 1)
Molecular Shapes Lab (Day 1 & 2)
Exit Ticket

8. Writing an Abstract

9. What is an abstract? A concise summary of your experiment
Summarized in 250 words or less
STEM Fair judges will read over your abstract to understand what you did in your project

10. Components of an Abstract
Problem Statement and hypothesis
Brief explanation of experimental procedure
A brief overview of results
With quantitative data included
Conclusion
Application and (or) relevance of findings
Write in past tense and passive voice

11. Example # 1
This project will exdplain whether or not antibacterial soap really kill germs. Antibacterial soap is known to be the most germ killing soap. To perform this experiment you must have a veriable and a control. The variable will be the antibacterial soap in which you will have to test three differnt times for each of the 3 soaps. The soaps will be Daial with antibacterial and dial without antibacterial, lever2000 with antibacterial and Lever without antibacterial, zest with antibactrial and zest without antibacterial. The control will be regular soap. The test will be used using petri dishes with chicken broth in them. Chicken broth makes it easier to see germs.

12. Example # 2
Advertisers are always touting more powerful and longer lasting batteries, but which batteries really do last longer, and is battery life impacted by the speed of the current drain? This project looks at which AA battery maintains its voltage for the longest period of time in low, medium, and high current drain devices. The batteries were tested in a CD player (low drain device), a flashlight (medium drain device), and a camera flash (high drain device) by measuring the battery voltage (dependent variable) at different time intervals (independent variable) for each of the battery types in each of the devices. The hypothesis was that Energizer would last the longest in all of the devices tested. The experimental results supported the original hypothesis by showing that the Energizer performs with increasing superiority, the higher the current drain of the device. The experiment also showed that the heavy-duty non-alkaline batteries do not maintain their voltage as long as either alkaline battery at any level of current drain.

13. STEM Fair Dates December 15th: Conclusion Re-Dos
December 19th: Abstract
December 22nd: Abstracts Returned
Re-Dos are due through to Mr. Klotz
January 9th: In-Class Presentations
January 29th: Howard HS STEM Fair
Tell them we will discuss board stuff on the Monday before winter break

14. Drawing Lewis Structures

15. Lewis Structures
Visual representation of the number of valence electrons in an atom

16. How to draw Lewis structures
Write the symbol of the element
Pretend there are 4 sides
Use dots to represent the valence electrons around the symbol
Place one dot on each side of the element before you form pairs
Exception: If there are only 2 valence electrons, they both go on the same side

17. Lewis Structures
C 1s2 2s2 2p2 • • • C •

18. Lewis Structures
Examples
Mg 1s2 2s2 2p6 3s2 • Mg •

19. Lewis Structures
Cl 1s2 2s2 2p6 3s2 3p5 • • • • Cl • • •

20. [ ] • • • • • • • • Cl -1 Lewis Structures Cl 1s2 2s2 2p6 3s2 3p5

21. VSEPR Theory Notes

22. Valence – Shell Electron Pair Repulsion Theory (VSEPR)
In a small molecule, the pairs of valence electrons are arranged as far apart from each other as possible
Explains why atoms form certain shapes when they bond together

23. Linear
Bonds Formed: 2
Lone Pairs: 0
Bond Angle: 180o

24. Trigonal Planar
Bonds Formed: 3
Lone Pairs: 0
Bond Angle: 120o

25. Tetrahedral
Bonds Formed: 4
Lone Pairs: 0
Bond Angle: 109.5o

26. Trigonal Pyramidal Bonds Formed: 3 Lone Pairs: 1
Bond Angle: <109.5o

27. Bent (Tetrahedral) Bonds formed: 2 Lone Pairs: 2
Bond Angle: <109.5o

28. Bent (Trigonal Planar)
Bonds Formed: 2
Lone Pairs: 1
Bond Angle: <120o

29. Trigonal Bipyramidal Bonds Formed:5 Lone Pairs: 0
Bond Angle: 120o and 90o

30. Octahedral
Bonds formed:6
Lone Pairs: 0
Bond Angle: 900

31. Molecular Shapes Lab

32. Molecular Shapes Lab Directions
Draw a Lewis Dot Structure for the molecule
Make a model using the kit and draw the shape on your paper
Write the shape name
Write the bond angle
Skip POLARITY for now, and we will come back to this part
Be careful with the kits, do not drop or lose pieces!

33. Exit Ticket Draw the Lewis Structure for CO2
Determine the shape and bond angles of CO2 according to the VSEPR theory.