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Section 2: VSEPR Theory & Molecular Structure and Polarity. Note: Each student is to receive a molecular geometry handout. Valence Shell Electron Pair Repulsion Theory: VSEPR. The shape of a molecule may be predicted by the number of atoms and un-bonded electrons that surround an atom.
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Section 2:VSEPR Theory&Molecular Structure and Polarity Note: Each student is to receive a molecular geometry handout
Valence Shell Electron Pair Repulsion Theory: VSEPR The shape of a molecule may be predicted by the number of atoms and un-bonded electrons that surround an atom.
Linear: Bond Angle: 180 degrees Lone Pairs of Electrons = 0
Trigonal Planar Bond Angle = 120 degrees Lone Pairs of electrons = 0
Tetrahedral Bond Angle = 109.5 degrees Lone Pairs of electrons = 0
Triganol bipyramidal Bond Angle = 90 degrees and 120 degrees Lone Pairs of electrons = 0
Octahedral Bond Angle = 90 degrees Lone pairs of electrons = 0
Bond Polarity: When molecules develop charged sides because one atom is pulling harder on the valence electron than the other. Finding the bond polarity: Step 1: Find the electronegativities of each atom. Atoms with higher electronegativites pull harder on the electrons in bonding. Step 2: Draw arrows to the atoms with the higher electronegativities. Example: Water
Find the Lewis Dot Structure, polarity, and geometry for each: • NF3 3) CH3I 2) CO2
Activity: Find the Lewis Dot Structure, Geometric shape and Polarity. • H2O 2) NCl3 3) SiO2 4) CF4 *5) SF6 *6) NH3
Extras • CCl4 • AsBr3 • XeF4
Geometry Quiz: Find the Lewis dot structure, geometry, and polarity (20pts) • NF3 • SeH2 • CH4 • SiO2
Molecular Geometry Quiz (5 pts each): Draw the lewis dot structure, draw the polarities, & name the structure • CBr4 • CS2 • NHCl2