Final answer:
To determine if a molecule is polar or nonpolar, we consider the type of bonds and the molecular shape. If a molecule has polar bonds but is symmetric, the polarities cancel out and the molecule is nonpolar. If a molecule has polar bonds and is not symmetric, the molecule is polar.
Step-by-step explanation:
In order to determine if a molecule is polar or nonpolar, we need to consider the type of bonds and the molecular shape. If a molecule has polar bonds but the molecule is symmetric, the polarities cancel out and the molecule is nonpolar. On the other hand, if a molecule has polar bonds and the molecule is not symmetric, the polarities do not entirely cancel out and the molecule is polar.For example, water (H2O) is a polar molecule because it has polar bonds and the molecule is not symmetric. The oxygen atom in water is more electronegative than the hydrogen atoms, causing the molecule to have a partial negative charge near the oxygen atom and partial positive charges near the hydrogen atoms.Carbon dioxide (CO2) is a nonpolar molecule because it has polar bonds but the molecule is linear and symmetric. The two carbon-oxygen bonds in carbon dioxide are polar, but the partial charges cancel out due to the molecule's linear shape. As a result, carbon dioxide has a symmetrical distribution of charge and is nonpolar.