tailieunhanh - Ebook Chemistry - A molecular approach (4/E): Part 2

(BQ) Part 2 book “Chemistry - A molecular approach” has contents: Liquids, solids, and intermolecular forces; solids and modern materials, chemical kinetics, chemical equilibrium, aqueous ionic equilibrium, free energy and thermodynamics, radioactivity and nuclear chemistry, organic chemistry, and other contents. | C hapte r 10 Chemical Bonding II: Molecular Shapes, Valence Bond Theory, and Molecular Orbital Theory No theory ever solves all the puzzles with which it is confronted at a given time; nor are the solutions already achieved often perfect. —Thomas Kuhn (1922–1996) Artificial Sweeteners: Fooled by Molecular Shape  427 Valence Bond Theory: Orbital Overlap as a Chemical Bond  445 VSEPR Theory: The Five Basic Shapes 428 Valence Bond Theory: Hybridization of Atomic Orbitals 447 VSEPR Theory: The Effect of Lone Pairs 432 VSEPR Theory: Predicting Molecular Geometries  437 Molecular Orbital Theory: Electron Delocalization 460 K e y L ea r n i n g O u tcome s   4 7 5 Molecular Shape and Polarity  440 426 426 2015/11/20 7:14 PM I n Chapter 9, we examined a simple model for chemical bonding called the Lewis model. We saw how this model helps us to explain and predict the combinations of atoms that form stable molecules. When we combine the Lewis model with the idea that valence electron groups repel one another—the basis of an approach known as VSEPR theory—we can predict the general shape of a molecule from its Lewis structure. We address molecular shape and its importance in the first part of this chapter. We then move on to explore two additional bonding theories—called valence bond theory and molecular orbital theory— that are progressively more sophisticated, but at the cost of being more complex, than the Lewis model. As you work through this chapter, our second on chemical bonding, keep in mind the importance of this topic. In our universe, elements join together to form compounds, and that makes many things possible, including our own existence. ▲ Similarities in the shape of sucrose and aspartame give both molecules the ability to stimulate a sweet taste sensation. Artificial Sweeteners: Fooled by Molecular Shape Artificial sweeteners, such as aspartame .