Arrange the following elements in order of increasing first ionization energy . Br, Cl, Se

Question

Quizplus · Accepted Answer

First ionization energy generally increases across a period (due to increasing nuclear charge) and decreases down a group (due to increasing atomic radius). Se is in the same period as Br and Cl but in a group to the left, making its ionization energy the lowest. Cl is to the right of Br in the same period, making its ionization energy the highest. Therefore, the order is Se < Br < Cl.

Arrange the Following Elements in Order of Increasing First Ionization