Which of the following elements has the smallest ionization energy
A) Li
B) Na
C) Be
D) K
E) Rb

Question

Quizplus · Accepted Answer

Rb (Rubidium) has the smallest ionization energy among the given options. Ionization energy generally decreases down a group in the periodic table because the outer electrons are farther from the nucleus and are more easily removed. Rb is located below all the other elements listed in the alkali metal group, making its ionization energy the lowest.

Which of the Following Elements Has the Smallest Ionization Energy