Which statement about sodium ion formation is true?

• A. Gains an electron
• B. Shares electrons
• C. Loses two electrons
• D. Loses an electron

Answer: (D)

Sodium tends to form ions by losing its single valence electron to reach a stable, noble-gas-like configuration. Because it has one electron in the outer shell, removing that electron gives a positively charged ion, Na+, with a low enough ionization energy that this loss is favored. This is why the true statement is that sodium loses an electron. Gaining an electron would make a negatively charged ion, which isn’t how sodium typically behaves in compounds. Sharing electrons describes covalent bonds rather than forming a charged ion, and losing two electrons would require far more energy and would produce a +2 charge, which doesn’t match sodium’s common chemistry.