Which bond type is associated with the polarity of a molecule?

The correct choice is covalent bonds, primarily because polarity in a molecule arises from the difference in electronegativity between the atoms involved in a covalent bond. When two atoms share electrons, if they have different electronegativities, the shared electrons will spend more time closer to the atom with the higher electronegativity. This uneven distribution of electron density creates a dipole moment, leading to a polar molecule.

In contrast, ionic bonds form through the transfer of electrons from one atom to another, resulting in charged ions. While ionic compounds can exhibit polarity when dissolved in water, the bond itself is not polar in the same way covalent bonds can be. Metallic bonds involve a sea of delocalized electrons and do not contribute to molecular polarity. Hydrogen bonds, although important in biological systems and molecular interactions, are a type of dipole-dipole interaction that occurs between polar molecules rather than a bond type that creates polarity itself. Hence, covalent bonds are fundamental in determining whether a molecule is polar or nonpolar.