The first ionization energy of Be is greater than that of B. — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

Step 1: Analyze the bond dissociation energy of the halogen molecules. Step 2: Fluorine (F2) has abnormally low bond dissociation energy (~158.8 kJ/mol) because the small size of the fluorine atoms leads to severe lone pair-lone pair repulsions. Step 3: This low value is exceptionally close to the bond dissociation energy of Iodine (I2, ~151 kJ/mol), which has a weak bond primarily due to its very large atomic size. Therefore, F2 and I2 have almost identical bond dissociation energies.