Which of the following properties of halogens increase with increasing atomic number?<br>(I) Ionizat β p Block Elements Chemistry Question
Question
Which of the following properties of halogens increase with increasing atomic number?<br>(I) Ionization energy<br>(II) Ionic radius<br>(III) Bond energy of the X2 molecule<br>(IV) Enthalpy of vaporisation
π‘ Solution & Explanation
Step 1: Bond dissociation energy (BDE) is inversely proportional to the bond length between two atoms of similar periods. Step 2: Across the third period, atomic size decreases from Phosphorus (P) to Sulfur (S) to Chlorine (Cl). Consequently, the bond lengths of their respective bonds with oxygen increase in the order: Cl-O < S-O < P-O. Step 3: Since shorter bonds are stronger and require more energy to break, the bond dissociation energy decreases in the order: Cl-O > S-O > P-O, which corresponds to option (d).