The correct increasing order of the second ionization enthalpies for the elements Carbon ( C ), Nitrogen ( N ), Oxygen ( O ), and Fluorine ( F ) is:

Step-by-step solution

The second ionization enthalpy is the energy required to remove an electron from the unipositive cation of an element. First, write the outermost electronic configurations of the unipositive cations: C ⁺ : 2 s ² 2 p ¹ N ⁺ : 2 s ² 2 p ² O ⁺ : 2 s ² 2 p ³ F ⁺ : 2 s ² 2 p ⁴ Generally, ionization enthalpy increases across a period from left to right. However, O ⁺ has a stable half-filled p-orbital configuration ( 2 p ³ ). Because of this extra stability, removing an electron from O ⁺ requires more energy than removing