Answer (2)
Sol. F > Cl : Fluorine has higher first ionisation energy than chlorine due to its smaller atomic size, leading to greater effective nuclear charge and tighter hold on the valence electron despite higher electron-electron repulsion in F. The given order Cl > F is incorrect. tThe actual order is F > Cl.
2). K > Na > Mg > Al : Metallic character decreases from Left to Right across the period and increases from Top to Bottom).
Which of the following is the correct order with respect to the property indicated? (1) Cl > F (Ionisation energy) (2) K2O > Na2O > Al2O3 (Basic nature) (3) K > Na > Al > Mg (Metallic character) (4) None of these