Which statement about polarity is true?

• A. Polarity is determined solely by the number of atoms
• B. A molecule is polar only if it is very large
• C. Polarity arises from differences in electronegativity between atoms
• D. A molecule is polar only if it contains a metal

Answer: (C)

Polarity comes from differences in how strongly atoms attract electrons—electronegativity. When two bonded atoms have different electronegativities, the more electronegative atom pulls electron density toward itself, creating a partial negative charge on that atom and a partial positive charge on the other. This separation of charge is what we call a polar bond, and the overall polarity of a molecule depends on the arrangement of these bonds: if the bond dipoles don’t cancel due to geometry, the molecule is polar (as in water). The size or number of atoms alone doesn’t determine polarity, and a molecule doesn’t need a metal to be polar—many polar molecules are composed only of nonmetals.