Which of the following elements would you expect to have the highest ionization energy value, and why?

A. Chlorine (Cl), because it has a low effective nuclear charge and low radius

B. Fluorine (F), because it has a large radius and naturally forms a negative ion

C. Lithium (Li), because it has a small radius and naturally forms a positive ion

D. Neon (Ne), because it has a high effective nuclear charge and small radius

Neon, Ne, would have the highest ionization energy because it has a high effective nuclear charge and small radius.

D. Neon (Ne), because it has a high effective nuclear charge and small radius

Explanation:

Ionization energy is the amount of energy required to remove an electron from the valence orbital.

Chlorine (Cl) and fluorine (F) are halogens which have a general valence configuration of ns²np⁵ and are highly electronegative

Lithium (Li) is an alkali metal with a valence configuration of ns¹ and has a tendency to lose electrons readily

Neon (Ne) is a noble gas with a valence configuration of ns²np⁶. Here the outer shells have a complete octet and stable configuration which makes it difficult to remove electrons. In addition the high nuclear charge and small radius of Ne results in a strong force of attraction between the nucleus and the valence electrons. Therefore, Ne would have the highest ionization energy value.