Question

Which of the following has the largest ionization enthalpy?

• A. $Mg$
• B. $P$
• C. $F$
• D. $Ar$

Answer 1

The correct option is D $Ar$

Ionization energy is the minimum amount of energy required to remove the most loosely bound electron (the valence electron) of an isolated gaseous atom.

The following factors affect the ionization energy:
a) Atomic radius
b) Effective nuclear charge
c) Electronic configuration

Among the four, $Ar$ has an octet configuration in its outermost shell, which is the most stable electronic configuration and removal of electron becomes very difficult. Hence ionization energy is highest for $Ar$.