Which factor best explains the partial negative charge on the oxygen atom in a water (H_2O) molecule?

• A. The water molecule is linear, causing electron density to accumulate on oxygen.
• B. Oxygen is more electronegative than hydrogen, attracting shared electrons closer to itself.
• C. Hydrogen atoms donate electrons to oxygen, resulting in a full negative charge.
• D. Oxygen has a larger atomic radius than hydrogen, causing it to hold electrons more loosely.

Answer: (B)

Verified step by step guidance

1. Understand that the question is asking about the reason for the partial negative charge on the oxygen atom in a water molecule (H\_2O).
2. Recall that in a covalent bond, electrons are shared between atoms, but the sharing is not always equal. The atom that attracts electrons more strongly will have a partial negative charge.
3. Identify the concept of electronegativity, which is the tendency of an atom to attract shared electrons in a chemical bond. Oxygen is more electronegative than hydrogen.
4. Recognize that because oxygen is more electronegative, it pulls the shared electrons in the O-H bonds closer to itself, creating a partial negative charge on oxygen and partial positive charges on the hydrogens.
5. Note that the molecular shape of water is bent, not linear, and that atomic radius does not cause a partial negative charge by itself; the key factor is the difference in electronegativity.