Which of the following pairs of atoms forms a nonpolar covalent bond?

• A. O-H
• B. Cl-Cl
• C. H-Cl
• D. N-H

Answer: (B)

Verified step by step guidance

1. Understand that a nonpolar covalent bond occurs when two atoms share electrons equally, which typically happens when the atoms have the same or very similar electronegativities.
2. Recall that electronegativity is a measure of an atom's ability to attract shared electrons in a bond. The greater the difference in electronegativity between two atoms, the more polar the bond becomes.
3. Examine each pair of atoms and consider their electronegativities: O (oxygen), H (hydrogen), Cl (chlorine), and N (nitrogen).
4. Note that the pair Cl-Cl consists of two identical atoms, so their electronegativities are exactly the same, meaning the electrons are shared equally, resulting in a nonpolar covalent bond.
5. For the other pairs (O-H, H-Cl, N-H), the atoms have different electronegativities, so the bonds are polar covalent rather than nonpolar.