Chapter 3- Molecular Shape and Structure. What we are going to learn. How the number of bonds and lone pairs affect the geometry of molecules. (VSEPR) How the geometries work with polarity to make a dipole moment. Two theories of bonding Valence Bond Theory: Atomic orbital hybridization.
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
What we are going to learn • How the number of bonds and lone pairs affect the geometry of molecules. (VSEPR) • How the geometries work with polarity to make a dipole moment. • Two theories of bonding • Valence Bond Theory: Atomic orbital hybridization. • Molecular orbital theory.
VSEPR:Valence Shell Electron-Pair Repulsion • Basic Principle: Electrons are negatively charged, they want to stay as far away from each other as possible. • Electron pairs show the most repulsion. • Single bonds can be treated the same as double and triple bonds.
Some Definitions • Steric Number: # bonds+# electron pairs • Coordination Number: number of bonded atoms Steric #: 4 Coord. #:3 Steric #: 5 Coord. #:5 Steric #: 6 Coord. #:5
Some (more) Definitions • Electron geometry: geometry including if you “saw” electron pairs • Molecular geometry: geometry where you don’t “see” electron pairs • Bond angle: angle between bonds. EG:Tetrahedral MG: Trig. pyramidal EG:Trig. bipyramidal MG: Trig. bipyramidal EG:Octahedral MG: Square Pyramidal
Pull out your worksheet, candy and toothpicks! Thanks to http://www.chemmybear.com/shapes.html for all animations on following slides!
Steric Number 3 Examples: SO3, BF3, CO32- Examples: SO2, CCl2
Steric Number 4 Examples: CH4, SiH4, PO4 Examples: NH3, PI3 Examples: H2O, OF2
Steric Number 5 Examples: PCl5, SbF5 Examples: TeCl4, SF4 Examples: ClF3, SeO32- Examples: I3-, XeF2
Steric Number 6 Examples: XeF4, ClF4- Examples: IF5, BrF5 Examples: SF6, Mo(CO)6
Going Back to Lewis Structures we did previously: Which bonds are polar?