How does the size of oxygen’s nucleus affect the distribution of electrons in a water (H₂O) molecule?

• A. The size of the nucleus has no effect on the electron distribution in the water molecule.
• B. A smaller nucleus causes electrons to be more strongly attracted to the hydrogen atoms.
• C. A larger nucleus increases the attraction for electrons, causing them to be drawn closer to the oxygen atom.
• D. A larger nucleus decreases the attraction for electrons, causing them to be distributed more evenly between hydrogen and oxygen.

Answer: (C)

Verified step by step guidance

1. Understand the relationship between the size of the nucleus and its ability to attract electrons. The nucleus contains protons, which are positively charged, and these protons exert an electrostatic force on the negatively charged electrons.
2. Recall that the size of the nucleus is related to the number of protons and neutrons it contains. A larger nucleus typically means more protons, which increases the positive charge and the ability to attract electrons.
3. In the case of the water molecule (H₂O), oxygen is more electronegative than hydrogen because it has a higher nuclear charge (more protons). This means oxygen attracts the shared electrons in the covalent bonds more strongly than hydrogen does.
4. If the size of oxygen’s nucleus increases, the number of protons in the nucleus would also increase. This would enhance the nucleus's ability to attract electrons, pulling the shared electrons in the water molecule closer to the oxygen atom.
5. Conclude that a larger nucleus increases the attraction for electrons, causing them to be drawn closer to the oxygen atom, which is consistent with the correct answer provided in the problem.