What characterizes a polar molecule?

A polar molecule is characterized by having a partial positive charge at one end and a partial negative charge at the other. This polarity arises due to the difference in electronegativity between the atoms involved in the molecule, which leads to an unequal sharing of electrons. When one atom in a bond attracts the shared electrons more strongly, it creates a dipole moment, resulting in one side of the molecule being slightly positive and the other side being slightly negative.

This uneven distribution of charge is what gives polar molecules their unique properties, such as higher boiling and melting points compared to nonpolar substances. Water is a classic example of a polar molecule; its structure allows it to exhibit such characteristics, which are essential for many of its roles in chemical reactions and biological systems.