Chemistry Jacqueline P. Hancock Covalent Bonding Chemistry Jacqueline P. Hancock

Worksheet..Answer Questions (15min) Notes(remainder of class) EQ1: How can we distinguish molecular compounds from ionic compounds and identify information of a molecular formula Read Section 8:1 Worksheet..Answer Questions (15min) Notes(remainder of class) Assignment-Homework...

Heading: Section 2 Pre-Reading Take a few minutes (20) to re-read Ch. 8 Section 2 Answer these questions on a left page 1. How are single bonds formed and represented? 2. How are double bonds formed and represented? 3. What is a coordinate covalent compound and why is it important to stability?

Lewis Structure Practice CH3I H2O Molecule of Fluorine HBr NH3 NI3

Homework Page 220 #7 & 8 7. Draw electron dot structures for each molecule a. chlorine b. bromine c. iodine 8. The following molecules have single covalent bonds. Draw an electron dot structure for each. a. H2O2 b. PCl3

Coordinate Covalent Compounds compounds in which an atom gives a pair of unshared electrons to another in a compound to reach an octet * if central atom does not have an octet, move electrons from outer atoms to form double or triple bonds

Examples of Coordinate Covalent, Double, and Triple Bonds Left page of INB CO2 N2 C2H2 SO3 ICl2-

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Lewis Structure Quiz You will have 15 minutes to complete 5 structures. No talking during or after the quiz No cell phones, etc. Place completed quizzes on table in front of class.

EQ 1 HOT Questions & Summary Write Summary of EQ 1. Make sure you answered all of your HOT questions Write Higher Order of Thinking Questions 3 level 1 question 3 level 2 questions 1 level 3 question

Essential Question 2 How will you describe the molecular geometry of a molecule. Cool video: Check out THIS ionic crystal lattice!! Molecular Geometry-Applies to any Lewis diagram. (Involved in covalent bonding)

Molecular Geometry Use your knowledge of VSEPR to complete the critical thinking exercise.

VSEPR Theory Valence Shell Electron Pair Repulsion Each bonding group or lone pair of electrons spreads out as far as possible from every other bonding group or lone pair of electrons. Think 3D!

Electron Pair vs. Molecular Geometry Electron pair geometry describes both bonds AND lone pairs located around the central atom. Molecular geometry describes only the bonds located around the central atom. Molecular geometry is a subset of electron pair geometry.

Practice How many bonding groups are around the central atom? 4 How many lone pairs around the central atom?

Practice How many bonding groups are around the central atom? 3 How many lone pairs are around the central atom? 1

Practice How many bonding groups are around the central atom? 3 How many lone pairs are around the central atom?

Practice How many bonding groups are around the central atom? 2 How many lone pairs are around the central atom?

Electron Pair Geometry: Overview The shape of the molecule including both bonds and lone pairs Linear 2 e- groups from central atom Trigonal Planar 3 e- groups from center Tetrahedral 4 e- groups from center Any of these lobes (electron groups) can be either lone pairs or covalent bonds

REMEMBER ELECTRON PAIR GEOMETRY and MOLECULAR GEOMETRY are not the same thing. EPG describes all electron groups (including lone pairs) MG describes only bonding groups

2 Electron Groups Electron pair geometry: Linear 2 bonding groups 0 lone pairs Molecular geometry: Linear Example: CO2 Double and triple bonds count as just ONE bonding group!!!

3 Electron Groups Electron pair geometry: Trigonal Planar 3 bonding groups 0 lone pairs Molecular geometry: Trigonal planar Example: NO3- Double and triple bonds count as just ONE bonding group This Lewis structure also shows the molecular shape (trigonal planar).

3 Electron Groups Electron pair geometry: Trigonal Planar 2 bonding groups 1 lone pair Molecular geometry: Bent Example: NO2- Double and triple bonds count as just ONE bonding group Lone pair is one of the three electron groups around the central atom

4 Electron Groups Electron pair geometry: Tetrahedral 4 bonding 0 lone pairs Molecular geometry: Tetrahedral Example: CH4 This Lewis structure does NOT show the tetrahedral molecular shape. It DOES show the four electron groups.

4 Electron Groups Electron pair geometry: Tetrahedral 3 bonding 1 lone pair Molecular geometry:Trigonal Pyramidal Example: NH3 This Lewis structure does NOT show the molecular shape. It DOES show the four electron groups. Lone pair is one of the four electron groups around the central atom

4 Electron Groups Electron pair geometry: Tetrahedral 2 bonding groups 2 lone pairs Molecular geometry: Bent/Angular Example: H2O This Lewis structure shows both the molecular shape and the four electron groups Lone pairs are two of the four electron groups around the central atom

Molecular Geometry: Overview The shape of the molecule including just bonds between atoms. 2 e- groups from central atom: If 2 bonds/0 lone pairs: Linear 3 e- groups from central atom: 3 bonds/0 lone pairs: Trigonal planar 2 bonds/1 lone pair: Bent 4 e- groups from central atom: 4 bonds/0 lone pairs: Tetrahedral 3 bonds/1 lone pair: Trigonal pyramidal 2 bonds/2 lone pairs: Bent

Sketches of Molecular Geometry Sketches (on homework, quizzes, and tests) should show the shape of the molecule in three dimensions:

Exceptions to the Octet Rule (SF6, BrF5, XeF4, IF7 ) (Beyond the scope of this class)

EQ 2 HOT Questions & Summary Write Summary of EQ 2. Make sure you answered all of your HOT questions Write Higher Order of Thinking Questions 3 level 1 question 3 level 2 questions 1 level 3 question