Which of the following sets contains only elements that typically form cations in binary ionic compounds?

• A. Na, Mg, Al
• B. N, P, As
• C. F, Br, I
• D. O, S, Cl

Answer: (A)

Verified step by step guidance

1. Step 1: Understand what a cation is. A cation is a positively charged ion formed when an atom loses one or more electrons. In binary ionic compounds, cations are typically metals or elements that tend to lose electrons.
2. Step 2: Identify the elements in each set and determine their typical ionic charges. Metals (usually on the left side of the periodic table) tend to form cations, while nonmetals (usually on the right side) tend to form anions (negatively charged ions).
3. Step 3: Analyze the first set: Na (Sodium), Mg (Magnesium), and Al (Aluminum). All three are metals and commonly form positive ions (Na⁺, Mg²⁺, Al³⁺), so they typically form cations.
4. Step 4: Analyze the other sets: N, P, As are nonmetals and usually form anions; F, Br, I are halogens and typically form anions; O, S, Cl are also nonmetals and typically form anions. Therefore, these sets do not contain only cations.
5. Step 5: Conclude that the set containing only elements that typically form cations in binary ionic compounds is Na, Mg, and Al.