Which statement best explains the difference between polar and nonpolar covalent bonds?

Nonpolar covalent bonds involve two atoms that have equal electonegativity whereas polar covalent bonds involve two atoms that are unequal in their electronegativity.

Explanation:

Polar covalent bonding is a type of chemical bond where a pair of electrons is unequally shared between two atoms.If the electronegativity of two atoms is basically the same, a nonpolar covalent bond will form, and if the electronegativity is slightly different, a polar covalent bond will form.

A covalent bond is a force that joins two atoms of non-metallic elements to form a molecule. Atoms share pairs of electrons from their most superficial layer (called the valence layer) to achieve the stability of the molecule that has been formed with the bond and thus comply with the octet rule.

On the other side, electronegativity refers to the tendency of the atom of a given element to attract electrons.

So, the covalent bond between two atoms can be polar or nonpolar.  

Polarity depends on the difference in electronegativity of the joining elements. The greater the electronegativity difference, the greater the polar character of the bond. The most electronegative element will be the one that most strongly attracts the shared electrons, then a negative partial charge will be generated on said element, while a positive partial charge will be generated on the other element (less electronegative).

Finally, nonpolar covalent bonding occurs when pairs of electrons are shared between atoms that have the same or very similar electronegativity, favoring an equitable distribution of electrons.

In summary, the correct answer is: Nonpolar covalent bonds involve two atoms that have equal electonegativity whereas polar covalent bonds involve two atoms that are unequal in their electronegativity.