Arrange the following elements in order of increasing first ionization energy:
S, Ar, Ca

Question

Quizplus · Accepted Answer

First ionization energy generally increases across a period (from left to right) and decreases down a group (from top to bottom) in the periodic table. Calcium (Ca) is an alkaline earth metal, sulfur (S) is a nonmetal, and argon (Ar) is a noble gas. Since Ca is to the left of S and Ar in the same period, and Ar is a noble gas with a full valence shell, making it more stable and less willing to lose an electron, the order of increasing first ionization energy is Ca < S < Ar.

Arrange the Following Elements in Order of Increasing First Ionization