9: Basic Concepts of Covalent Bonding
- Page ID
- 170027
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- 9.1: Covalent Bonding Fundamentals
- Fundamentally, atoms form a chemical bond because the overall energy of the bonded atoms is lower than the overall energy of the original, unbonded atoms. In this section we consider the energetics of covalent bonding and introduce two models for a covalent bond.
- 9.2: Interpreting Lewis Structures
- Lewis Dot Structures should be review from your preparatory chemistry course. In this section, we will outline several key concepts applied in working with Lewis Dot Structures.
- 9.3: Drawing Lewis Structures
- A Lewis structure is a way to show how atoms share electrons when they form a molecule. Lewis structures show all of the valence electrons in an atom or molecule.
- 9.4: Resonance Lewis Structures
- Resonance is a way of describing delocalized electrons within certain molecules or polyatomic ions where the bonding cannot be expressed by a single Lewis formula. A molecule or ion with such delocalized electrons is represented by several contributing structures (also called resonance structures or resonance contributors).
- 9.5: Strength of Covalent Bonds
- In proposing his theory that octets can be completed by two atoms sharing electron pairs, Lewis provided scientists with the first description of covalent bonding. In this section, we expand on this and describe some of the properties of covalent bonds. The stability of a molecule is a function of the strength of the covalent bonds holding the atoms together.
- 9.6: The VSEPR Model
- The VSEPR model can predict the structure of nearly any molecule or polyatomic ion in which the central atom is a nonmetal, as well as the structures of many molecules and polyatomic ions with a central metal atom. The VSEPR model is not a theory; it does not attempt to explain observations. Instead, it is a counting procedure that accurately predicts the three-dimensional structures of a large number of compounds, which cannot be predicted using the Lewis electron-pair approach.
- 9.7: Molecular Polarity
- Compounds with polar covalent bonds have electrons that are shared unequally between the bonded atoms. The polarity of such a bond is determined largely by the relative electronegativites of the bonded atoms. The asymmetrical charge distribution in a polar substance produces a dipole moment, which is the product of the partial charges on the bonded atoms and the distance between them.