Concept:Polarity of a covalent molecule depends on the unequal sharing of bonding electrons between atoms.
Explanation:Electronegativity measures an atom’s ability to attract shared electrons in a chemical bond.
When two different atoms form a covalent bond, the atom with higher electronegativity pulls the electron pair closer to itself.
This creates a partial positive charge on one atom and a partial negative charge on the other, making the bond polar.
A large electronegativity difference between bonded atoms leads to a polar covalent molecule.
A small or zero electronegativity difference results in a nonpolar covalent molecule.
Therefore, the periodic property used to judge molecular polarity is electronegativity.
Answer:D. electronegativity