Consider the following isoelectronic species: N ³⁻ , O ²⁻ , F ⁻ , Na ⁺ , and Mg ²⁺ . Which of the given species simultaneously possesses the smallest ionic radius and the highest ionization enthalpy?

Step-by-step solution

The given species N ³⁻ , O ²⁻ , F ⁻ , Na ⁺ , and Mg ²⁺ are isoelectronic, each containing 10 electrons. For isoelectronic species, the effective nuclear charge increases with an increase in atomic number ( Z ). Mg ²⁺ has the highest atomic number ( Z=12 ). A higher effective nuclear charge pulls the electron cloud closer to the nucleus, resulting in the smallest ionic radius. Consequently, the outermost electrons in Mg ²⁺ are held most tightly by the nucleus, meaning it requires the maximum energy to remove an elec