distance and bond strength are between possible drawing configurations and
really indicate a hybrid condition. To represent this situation, the possible
alternatives are drawn with arrows between them. Classic examples are sulfur
trioxide and benzene. These structures are shown in Chapters 13 and 14,
respectively, but are repeated here as examples.
Sulfur trioxide resonance structures:
Benzene resonance structures:TIP
Two theories explain molecular structure: VSEPR theory uses valence shell electron pair
repulsion.Hybridization theory uses changes in the orbitals of the valence electrons.MOLECULAR GEOMETRY—VSEPR—AND
HYBRIDIZATION
VSEPR—Electrostatic Repulsion
Properties of molecules depend not only on the bonding of atoms but also on the
molecular geometry—the three-dimensional arrangement of the molecule’s
atoms in space. The combination of the polarity of the bonds and the geometry of
the molecule determine the molecular polarity. This can be defined as the uneven
distribution of the molecular charge. The chemical formula reveals little
information about a molecule’s geometry. It is only after doing many tests
designed to reveal the shapes of the various molecules that chemists developed
two different yet equally successful theories to explain certain aspects of their
findings. One theory accounts structurally for molecular bond angles. The other is
used to describe changes in the orbitals that contain the valence electrons of a