Chemistry

Question Analysis
This question evaluates the understanding of periodic trends in ionization energy and the ability to compare the ionization energies of different elements.

Key Concept Explanation
Ionization energy generally increases across a period from left to right due to increasing nuclear charge and decreasing atomic radius, which strengthen the attraction for valence electrons. Down a group, ionization energy decreases due to increasing atomic radius, which weakens the nuclear attraction for valence electrons.

Step-by-step Solution
1. Identify the position of potassium (K) in the periodic table: K is in Group 1, Period 4.
2. Compare the positions of the given elements with potassium:
Calcium (Ca) is in Group 2, Period 4.
Lithium (Li) is in Group 1, Period 2.
Rubidium (Rb) is in Group 1, Period 5.
Argon (Ar) is in Group 18, Period 3.
3. Use the periodic tre...