Which of the following elements is most likely to form an ion with a 2- charge, similar to oxygen?

• A. Cl (chlorine)
• B. Na (sodium)
• C. S (sulfur)
• D. Al (aluminum)

Answer: (C)

Verified step by step guidance

1. Understand that elements tend to form ions to achieve a stable electron configuration, often resembling the nearest noble gas configuration.
2. Recall that oxygen (O) commonly forms a 2- ion by gaining two electrons to complete its valence shell, achieving a full octet.
3. Identify the position of each element in the periodic table: Chlorine (Cl) is in group 17, Sodium (Na) in group 1, Sulfur (S) in group 16, and Aluminum (Al) in group 13.
4. Recognize that elements in group 16, like oxygen, have six valence electrons and tend to gain two electrons to form a 2- ion, similar to oxygen.
5. Conclude that sulfur (S), being in the same group as oxygen, is most likely to form a 2- ion, while the others typically form ions with different charges (Cl forms 1-, Na forms 1+, Al forms 3+).