Question

The stability of dihalides of Si, Ge, Sn and Pb increases steadily in the sequence

(a) PbX₂ << SnX₂ << GeX₂ << SiX₂

(b) GeX₂ << SiX₂ << SnX₂ << PbX₂

(c) SiX₂<< GeX₂ << PbX₂ << SnX₂

(d) SiX₂ << GeX₂ << SnX₂ << PbX₂ .

Answer 1

(c) : Due to the inert pair effect (the reluctance of ns² electrons of outermost shell to participate in bonding) the stability of M²⁺ ions (of group IV elements) increases as we go down the group.