Question

Arrange the following in increasing order of ionic radii: \( C^{4-}, N^{3-}, F^{-}, O^{2-} \).

• A. \( C^{4-}<N^{3-}<O^{2-}<F^{-} \)
• B. \( N^{3-}<C^{4-}<O^{2-}<F^{-} \)
• C. \( F^{-}<O^{2-}<N^{3-}<C^{4-} \)
• D. \( O^{2-}<F^{-}<N^{3-}<C^{4-} \)

Hint:

As negative charge increases on an ion, its ionic radius increases due to increased electron repulsion.

Answer 1

The Correct Option is C

Step 1: Understanding ionic radii trends.
- Anions have larger radii than their parent atoms due to electron-electron repulsions.
- More negative charge results in greater expansion of the electron cloud.
Step 2: Analyzing given ions.
- \( C^{4-} \) has the largest radius because it has gained the most electrons.
- \( N^{3-} \) is smaller than \( C^{4-} \) but larger than \( O^{2-} \).
- \( O^{2-} \) is smaller than \( N^{3-} \) but larger than \( F^{-} \).
- \( F^{-} \) has the smallest radius since it has the least electron gain.