Solution: The Lewis structure of CO 2 is O=C=O, with two extra lone pairs of electrons on each
oxygen atom so all three atoms have an octet structure.The double bond behaves just like a single bond for purposes of predicting molecular shape. This
compound has two groups of electrons around the carbon. According to the VSEPR theory, the two
sets of electrons will orient themselves 180° apart, on opposite sides of the carbon atom,
minimizing electron repulsion. Therefore, the molecular structure of CO 2 is linear.
POLARITY OF MOLECULES
BASIC CONCEPT
A molecule is polar if it has polar bonds and if the dipole moments of these bonds do not
cancel one another.Earlier we talked about the concept of the dipole moment in a polar covalent bond. If a molecule
has more than two atoms, there will be more than one bond. Each bond may or may not be a dipole,
and in such cases one can talk about the polarity of the molecule as a whole. A molecule is polar if it
has polar bonds and if the dipole moments of these bonds do not cancel one another (by pointing in
opposite directions, for example). The polarity of a molecule, therefore, depends on the polarity of
the constituent bonds and on the shape of the molecule. A molecule with only nonpolar bonds is
always nonpolar; a molecule with polar bonds may be polar or nonpolar, depending on the
orientation of the bond dipoles. For instance, CCl 4 has four polar C–Cl bonds. According to the
VSEPR theory, the shape of CCl 4 is tetrahedral. The four bond dipoles point to the vertices of the
tetrahedron and cancel each other, resulting in a nonpolar molecule.