Chemistry

Question Analysis
This question evaluates the understanding of periodic trends in ionization energy, specifically how it changes across a period and the anomalies due to electron configuration.

Key Concept Explanation
Ionization energy generally increases from left to right across a period due to increasing nuclear charge and decreasing atomic radius. However, there are anomalies due to the extra stability of half-filled or fully filled subshells.

Step-by-step Solution
1. Identify the elements given: Carbon (C), Nitrogen (N), Oxygen (O), and Fluorine (F).
2. Determine their positions in the periodic table: C (Group 4A), N (Group 5A), O (Group 6A), F (Group 7A).
3. Recall that ionization energy generally increases from left to right across a period.
4. Note that Ni...