Final answer:
The degree of polarity of a bond is indicated by the electronegativity difference between the bonded atoms. Chemists characterize a bond as polar covalent when electrons are shared unequally, resulting in partial charges on the atoms.
Step-by-step explanation:
The degree of polarity of a bond is indicated by the electronegativity difference between the bonded atoms. Electronegativity is the ability of an atom to attract electrons. If the electronegativities of the bonded atoms are not equal, the bond is polarized toward the more electronegative atom, resulting in partial charges on the atoms.
Chemists characterize a bond as polar covalent when electrons are shared unequally between the bonded atoms. The atom with greater electronegativity acquires a partial negative charge, while the atom with lower electronegativity acquires a partial positive charge. This charge distribution produces a dipole moment in a polar substance.