The successive ionisation energies of an element are 165, 195, 556, and 595 kcal/mol. What is the ex — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

There is a massive jump in ionization energy between $IE_2$ (195) and $IE_3$ (556). This indicates the removal of the 3rd electron breaks a stable noble gas core, meaning the atom has exactly 2 valence electrons ($ns^2$).