The polarity of a molecule is intricately linked to its geometry, as the shape of the molecule influences the distribution of electrical charges.

To elaborate, the polarity of a molecule arises from two main factors: the difference in electronegativity between the constituent atoms and the symmetry of the molecule itself. Electronegativity quantifies an atom’s ability to attract a bonding pair of electrons. When two atoms with differing electronegativities bond together, the bonding electrons are drawn more towards the atom with the higher electronegativity. This creates a dipole moment, characterized by a separation of positive and negative charges. Consequently, one end of the molecule acquires a slight negative charge, while the opposite end exhibits a slight positive charge, classifying the molecule as polar.

Nevertheless, the overall polarity of the molecule is also contingent upon its geometric configuration. In cases where a molecule is symmetrical, the dipole moments can effectively cancel one another, leading to a nonpolar molecule. A prime example of this is carbon dioxide ($\text{CO}_2$), which has a linear structure and features two polar $\text{C=O}$ bonds. However, due to its linear geometry, the dipole moments are equal in magnitude but opposite in direction, resulting in their cancellation and rendering $\text{CO}_2$ nonpolar.

Conversely, if a molecule lacks symmetry, the dipole moments do not cancel, resulting in a polar molecule. A pertinent example is water ($\text{H}_2\text{O}$), which possesses a bent geometry and two polar $\text{O-H}$ bonds. In this case, the bent shape prevents the dipole moments from canceling out, establishing $\text{H}_2\text{O}$ as a polar molecule.

In conclusion, the polarity of a molecule is determined by both the electronegativity differences between its atoms and its geometric symmetry. A molecule may exhibit polar bonds yet remain nonpolar if it is symmetrical, allowing the dipole moments to cancel each other. Conversely, a molecule can be classified as polar if it possesses polar bonds and lacks symmetry, resulting in a net dipole moment.