Which pair of elements is most likely to react to form an ionic compound when brought together?

• A. O and Ne
• B. C and H
• C. Na and Cl
• D. N and Ar

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the nature of ionic compounds. Ionic compounds typically form between metals and nonmetals, where one element donates electrons (metal) and the other accepts electrons (nonmetal), resulting in the formation of ions.
2. Step 2: Identify the types of elements in each pair. For example, Na (sodium) is a metal, and Cl (chlorine) is a nonmetal, which makes them good candidates for ionic bonding.
3. Step 3: Analyze the other pairs: O (oxygen) and Ne (neon) are both nonmetals, with Ne being a noble gas that is very unreactive; C (carbon) and H (hydrogen) are both nonmetals and typically form covalent bonds; N (nitrogen) and Ar (argon) include a noble gas (Ar) which is generally inert.
4. Step 4: Recall that noble gases like Ne and Ar have full valence shells and rarely form compounds, so pairs involving noble gases are unlikely to form ionic bonds.
5. Step 5: Conclude that the pair consisting of a metal and a nonmetal (Na and Cl) is most likely to react to form an ionic compound due to the transfer of electrons from the metal to the nonmetal.