Chemical polarity concerns unequal distribution of electron density in a chemical bond or molecule. A polar molecule has a permanent electric dipole moment; the effects of individual bonds must be combined with their spatial arrangement. In a symmetric linear carbon dioxide molecule, opposing bond-dipole contributions cancel. In water, its bent molecular geometry prevents that cancellation, giving a permanent electric dipole moment.[ref]
A polar molecule has a nonzero permanent electric dipole moment because of its internal electric charge distribution. It can still have zero total electric charge. Water is polar; a nonpolar molecule has no permanent electric dipole moment.
A nonpolar molecule has no permanent electric dipole moment. This distinguishes its charge distribution from the separated partial charges of a polar molecule.
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Chemical polarity refers to the distribution of electrical charge over the atoms in a molecule. It describes how the bonding electrons are distributed between the atoms, which can lead to the formation of regions with partial positive and negative charges within the molecule. Polarity occurs due to differences in electronegativity between the atoms involved in a chemical bond. Electronegativity is the tendency of an atom to attract electrons towards itself.