Under what condition are polar covalent bonds formed?

Polar covalent bonds are formed when there is a difference in electronegativity between the two atoms involved in the bond. In this scenario, one atom has a stronger attraction for the shared electrons than the other. This unequal sharing of electrons leads to a distribution of charge, resulting in a partial positive charge on one atom and a partial negative charge on the other. Thus, the characteristic of polar covalent bonds arises from this unequal attraction for the shared bonding electrons, which is precisely why the provided answer is correct.

In contrast, the other conditions described represent different bonding scenarios. Atoms with the same electronegativity or those that share electrons equally typically result in nonpolar covalent bonds instead of polar ones. Additionally, when atoms are connected by ionic bonds, there is a complete transfer of electrons rather than sharing, which fundamentally differs from the nature of covalent bonding. Understanding these distinctions helps clarify the specific conditions under which polar covalent bonds are formed.