Chemistry

Question Analysis
This question involves comparing first ionization energies of isoelectronic species (all have 18 electrons). The main focus is on relating nuclear charge and ionic charge to ionization energy for isoelectronic particles.

Key Concept Explanation
For isoelectronic species:
Ionization energy increases with increasing nuclear charge (more protons attract electrons more strongly).
Anions have lower nuclear charge relative to their electron count than neutral atoms or cations, making electrons easier to remove.

Step-by-Step Solution
1. Confirm all species are isoelectronic (18 electrons) and list their nuclear charges (proton counts):
Ca²⁺: 20 proton...