Creating a Positive Learning Environment for Everyone Be respectful of your classmates Save conversation for clicker portions of lecture Put cell phones in “airplane” mode Turn off tablets Close laptops

Announcements Exam #3: Thursday, Dec. 7st, 7:00-8:30pm (Conflict: 5:00-6:30pm) No calculators allowed Conflicts to conflicts? Must TELL me by THIS Friday! Activity 3: Making Models of Molecules lab write-up due in Friday discussion (download sheet from website) Electronic HW Remaining Homework 6 – Type 2 due Wed, 11/29 by 7pm Homework 7 – Type 1 due Monday, 12/4 by 7pm Homework 8 – Type 1 due Wednesday, 12/6 by 7pm Review Questions for Exam III due Wed, 12/6 by 10pm Pre-lecture Assignments

Electronegativity

Overall goal: Atomic Structure Chemical Bonding 3D Molecular Structure Molecular Properties

Types of Bonding Ionic Bonding Polar Covalent Bonding Nonpolar Covalent Bonding

Clicker #1 Arrange the following bonds from the least polar to the most polar bond. C–F, Na–F, Ge–F, Si–F a) C–F < Ge–F < Si–F < Na–F b) Si–F < C–F < Ge–F < Na–F c) C–F < Si–F < Ge–F < Na–F d) Na–F < Ge–F < Si–F < C–F e) Na–F < C–F < Si–F < Ge–F

Clicker #2 How many electrons would hydrogen have to share in a covalent bond in order to have a noble gas electron configuration? A) 0 B) 2 C) 3 D) 6 E) 8

Clicker #3 Element “X” in this Lewis structure comes from period 4 (row 4) on the periodic table. What is its identity? A) F B) Cl C) Br D) S E) Se

General Guidelines… The total number of electrons in your Lewis structure must equal the total number of valence electrons. The least electronegative atom (usually written first) is typically the central atom (except for hydrogen). Follow the octet rule. Follow the duet rule for hydrogen. Trial and error – add double and triple bonds as necessary until octet (or duet) rule is satisfied & valence electrons add up.

Clicker #4 How many valence electrons are in NO3–? A) 4 B) 18 C) 23 D) 24 E) 32

Clicker #5 How many valence electrons are in BH3? A) 10 B) 8 C) 6 D) 4