7.53 Knowing the electron gain enthalpy values for O → O^- and O → O^2- as –141 and 702 kJ mol–1 respectively, how can you account for the formation of a large number of oxides having O^2- species and not O^- ? (Hint: Consider lattice energy factor in the formation of compounds).

HClO₄ is the most acidic compound.

Group number = 11 (Atomic number = 111)

Heavier element of p block do not from pπ− pπ bonds as their atomic orbital are so large and diffius that they cannot have effecitve overlapping.

The inertness of ? subshell electrons towards bond formation is known as inert pair effect. This effect increases down the group thus, for Sn,  oxidation state is more stable, whereas, for Pb,  oxidation state is more stable, i.e.,  is reducing while  is oxidising.