Bonding Part 3 Molecular Geometry PDF

Chapter Outline 10.1 Artificial Sweeteners: Fooled by Molecular Shape 10.2 VSEPR Theory: The Five Basic Shapes 10.3 VSEPR Theory: The Effect of Lone Pairs 10.4 VSEPR Theory: Predicting Molecular Geometries 10.5 Molecular Shape and Polarity 10.6 Valence Bond Theory: Orbital Overlap as a Chemical...

Chapter Outline 10.1 Artificial Sweeteners: Fooled by Molecular Shape 10.2 VSEPR Theory: The Five Basic Shapes 10.3 VSEPR Theory: The Effect of Lone Pairs 10.4 VSEPR Theory: Predicting Molecular Geometries 10.5 Molecular Shape and Polarity 10.6 Valence Bond Theory: Orbital Overlap as a Chemical Bond 10.7 Valence Bond Theory: Hybridization of Atomic Orbitals 10.8 Molecular Orbital Theory: Electron Delocalization Copyright © 2023 Pearson Canada Inc. 10 - 1 10.1 Artificial Sweeteners: Fooled by Molecular Shape 2 C12 H 22 O11 (s ) + 12 O 2 (g ) ⎯⎯ → 12 CO 2 (g ) + 11 H 2O (l )  r H  = − kJ Copyright © 2023 Pearson Canada Inc. 10 - 2 10.2 VSEPR Theory: The Five Basic Shapes valence shell electron pair repulsion (VSEPR) theory According to VSEPR theory, minimizing repulsions between electron groups on interior atoms of a molecule determine the geometry of the molecule electron groups – bonds and non- bonding electrons on the central atom Figure 10.1 Repulsion between Electron Groups Copyright © 2023 Pearson Canada Inc. 10 - 3 Three-Dimensional Representation For example, a tetrahedral molecular geometry can be represented as: Copyright © 2023 Pearson Canada Inc. 10 - 4 Two Groups: Linear Geometry the two double bonds repel repulsion between these two electron each other each other, groups, which can maximize their resulting in a linear geometry separation by assuming a 180° bond angle or a linear geometry. Beryllium often forms compounds with incomplete octets, as it does in this A double bond counts as one electron example. group. Copyright © 2023 Pearson Canada Inc. 10 - 5  Three Groups: Trigonal Planar Geometry three electron groups bond angles are close to the idealized 120° bond angle. Copyright © 2023 Pearson Canada Inc. 10 - 6 Linear and Trigonal Planar Geometry Notice that the balloons do not represent Like three balloons tied atoms, but electron groups. together, three electron groups adopt a trigonal planar geometry. Figure 10.2 Representing Electron Geometry with Balloons [CDV, LLC/Pearson Education] Copyright © 2023 Pearson Canada Inc. 10 - 7 Four Electron Groups: Tetrahedral Geometry Copyright © 2023 Pearson Canada Inc. 10 - 8 Example Determine the electron geometry and molecular geometry of NO3− Determine the electron geometry and molecular geometry of CCl4. A molecule with the formula AB3 has a trigonal planar geometry. How many electron groups are on the central atom? Copyright © 2023 Pearson Canada Inc. 10 - 9 Five Electron Groups: Trigonal Bipyramidal Geometry Copyright © 2023 Pearson Canada Inc. 10 - 10 Six Electron Groups: Octahedral Geometry Copyright © 2023 Pearson Canada Inc. 10 - 11 Example Determine the electron geometry and molecular geometry of PF5 Determine the electron geometry and molecular geometry of XeBr2F4 Copyright © 2023 Pearson Canada Inc. 10 - 12 10.3 VSEPR Theory: The Effect of Lone Pairs Four Electron Groups with Lone Pairs 4/1 Copyright © 2023 Pearson Canada Inc. 10 - 13 Nonbonding vs Bonding Electron Pairs Figure 10.3 Nonbonding versus Bonding Electron Pairs Copyright © 2023 Pearson Canada Inc. 10 - 14 Example: NH3 4/1 Copyright © 2023 Pearson Canada Inc. 10 - 15 Example: H2O (1 of 2) 4/2 Copyright © 2023 Pearson Canada Inc. 10 - 16 Example: H2O (2 of 2) Copyright © 2023 Pearson Canada Inc. 10 - 17 Effect of Lone Pairs on Molecular Geometry Figure 10.4 The Effect of Lone Pairs on Molecular Geometry Copyright © 2023 Pearson Canada Inc. 10 - 18 Example Determine the electron geometry and molecular geometry of NF3 Determine the electron geometry and molecular geometry of H2S Copyright © 2023 Pearson Canada Inc. 10 - 19 Five Electron Groups with Lone Pairs (1 of 3) 5/1 Copyright © 2023 Pearson Canada Inc. 10 - 20 Five Electron Groups with Lone Pairs (2 of 3) 5/2 Copyright © 2023 Pearson Canada Inc. 10 - 21 Five Electron Groups with Lone Pairs (3 of 3) 5/3 Copyright © 2023 Pearson Canada Inc. 10 - 22 Six Electron Groups with Lone Pairs (1 of 2) 6/1 Copyright © 2023 Pearson Canada Inc. 10 - 23 Six Electron Groups with Lone Pairs (2 of 2) 6/2 Copyright © 2023 Pearson Canada Inc. 10 - 24 TABLE 10.1 Electron and Molecular Geometries (1 of 3) *Count only the electron groups around the central atom. Each of the following is considered one electron group: a lone pair, a single bond, a double bond, a triple bond, or a single electron. Copyright © 2023 Pearson Canada Inc. 10 - 25 TABLE 10.1 Electron and Molecular Geometries (2 of 3) Copyright © 2023 Pearson Canada Inc. 10 - 26 TABLE 10.1 Electron and Molecular Geometries (3 of 3) Copyright © 2023 Pearson Canada Inc. 10 - 27 10.5 Molecular Shape and Polarity Copyright © 2023 Pearson Canada Inc. 10 - 28 Example: H2O Copyright © 2023 Pearson Canada Inc. 10 - 29 Interaction of Polar Molecules Figure 10.5 Interaction of Polar Molecules Copyright © 2023 Pearson Canada Inc. 10 - 30 Mix of Polar and Nonpolar Molecules Oil and water do not mix because water molecules are polar and the molecules that compose oil are nonpolar [Kip Peticolas/Fundamental Photographs] Copyright © 2023 Pearson Canada Inc. 10 - 31 Hybridization Mixing of s, p, d, f orbitals of atoms when they form bonds. - we will be interested in the hybridization of central atom only 1. Count electron groups around central atom - single bond, multiple bond, non-bonding electron pair each count as one group 2. Determine hybridization: - 2 groups around central atom -> s+p orbital = sp hybridization - 3 groups –> s+2p = sp2 - 4 groups –> s+3p = sp3 This is the max use of p-orbitals Copyright © 2023 Pearson Canada Inc. 10 - 32 Hybridization - 5 groups -> s+3p+d = sp3d - 6 groups -> -> s+3p+2d = sp3d2 Copyright © 2023 Pearson Canada Inc. 10 - 33 Writing Hybridization and Bonding Schemes TABLE 10.3 Hybridization Scheme from Electron Geometry Copyright © 2023 Pearson Canada Inc. 10 - 34