Office Hours:

1
Office Hours Monday 10-11am, Wednesday 5-6pm,
or by Appt. In PSBN 1511
2
To Improve Your Grade

• Prepare for class
• Read the book beforehand (at least try it
  once!)
• Work problems that I email you
• Study early and often
• Work as many problems as possible
• Work more than just the Webassign homework
• Only use the solutions guide when youre done
• Get help when you need it
• CLAS sections, drop-in schedule
• My Office hours
• Lab TA Office hours

3
Writing Lewis Structures

• Sum all valence electrons (including charges)
• Write Skeletal Structure
• Hydrogens are always terminal, Halogens usually
  terminal
• Often, more electronegative atoms on outside
• Often symmetric
• Make bonds (two electrons each)
• Add remaining electrons
• Make double/triple bonds to satisfy duet/octet
  rule (duet for hydrogen, octet for 2nd row
  elements)
• Minimize formal charges
• Check your work
• Correct of electrons? Octet rule satisfied?
  Resonance?

4
Writing Lewis Structures that Violate the Octet
Rule

• Proceed as before, drawing single bonds between
  all atoms
• Use the rest of the electrons to try to satisfy
  the octet rule for all atoms
• If you have Boron, you can leave it with 6
  electrons (3 bonds)
• If you have extra electrons after satisfying
  octet rule, place them on elements with
  available d orbitals (3rd row and beyond)
• Check your work

5
Formal Charges Conclusion

• All formal charges in a neutral molecule add to 0
• polyatomic
  ion add to the ion charge
• For molecules with 2nd row atoms, the correct
  Lewis structure minimizes formal charges
• For molecules with 3rd row or heavier atoms, no
  way to tell