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.įigure R.2.1Common Structures for Molecules and Polyatomic Ions That Consist of a Central Atom Bonded to Two or Three Other Atoms The VSEPR model is not a theory it does not attempt to explain observations. 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. Keep in mind, however, that the VSEPR model, like any model, is a limited representation of reality the model provides no information about bond lengths or the presence of multiple bonds. We continue our discussion of structure and bonding by introducing the valence-shell electron-pair repulsion (VSEPR) model (pronounced “vesper”), which can be used to predict the shapes of many molecules and polyatomic ions. This approach gives no information about the actual arrangement of atoms in space, however. Handout 8.6.2: VSEPR Lewis electron-pair approach can be used to predict the number and types of bonds between the atoms in a substance, and it indicates which atoms have lone pairs of electrons.
VSEPR (Valence Shale Electron Repulsion Theory)
