Which of the following arrangements indicates the correct decreasing order of ionization energy of period 3 elements?

A. Na, Al, P, Cl
B. Cl, P, Al, Na
C. Na, P, Cl, Al
D. Al, Na, P, Cl

Correct Answer: Option B

B. Cl, P, Al, Na

Explanation

As you move across a period, first ionization energy increases.