http://www.ck12.org Chapter 9. Covalent Bonding
9.4 Hybridization of Atomic Orbitals
Lesson Objectives
- Describe valence bond theory as it pertains to the formation of a covalent bond between atoms.
- Describe the process of electron promotion and hybridization during the formation of hybrid orbitals.
- Explain the relationship between electron domain geometry and the various types of hybrid orbitals.
- Distinguish between sigma and pi bonding.
Vocabulary
- hybridization
- hybrid orbitals
- pi bond (π)
- sigma bond (σ)
- valence bond theory
Check Your Understanding
Recalling Prior Knowledge
- How are electrons arranged in atomic orbitals?
- What is the difference between the electron domain geometry of a molecule and its molecular geometry?
Earlier in this chapter, you learned how to draw Lewis electron-dot structures for molecules and predict their shapes
using VSEPR theory. In this lesson, we will see how these concepts relate to the way in which electrons behave in
their atomic orbitals when a covalent bond forms.
Valence Bond Theory
You have learned that a covalent bond forms when the electron clouds of two atoms overlap with each other. In
a simple H 2 molecule, the single electron in each atom becomes attracted to the nucleus of the other atom in the
molecule as the atoms come closer together. An optimum distance between the two nuclei, equal to the bond length,
is eventually attained, and the potential energy reaches a minimum. At this point, a stable single covalent bond has
formed between the two hydrogen atoms. Other covalent bonds form in the same way as unpaired electrons from
two atoms “match up” to form the bond. In a fluorine atom, there is an unpaired electron in one of the 2porbitals.
When a F 2 molecule forms, the 2porbitals from each of the two atoms overlap to produce the F−F covalent bond.