The noble gases Kr, Xe, and Ar when arranged in the decreasing order of their ionization energies follow the order:
A) Ar Kr Xe.
B) Kr Ar Xe.
C) Ar Xe Kr.
D) Xe Kr Ar.
E) Xe Ar Kr.

Question

The noble gases Kr, Xe, and Ar when arranged in the decreasing order of their ionization energies follow the order:
A) Ar > Kr > Xe.
B) Kr > Ar > Xe.
C) Ar > Xe > Kr.
D) Xe > Kr > Ar.
E) Xe > Ar > Kr.

Quizplus · Accepted Answer

Ionization energy generally increases across a period due to increasing nuclear charge and decreases down a group as the outer electrons are farther from the nucleus. Since Ar, Kr, and Xe are in the same group with Ar being the highest and Xe the lowest, the order of decreasing ionization energy is Ar > Kr > Xe.

The Noble Gases Kr, Xe, and Ar When Arranged in the Decreasing