Question

Sol. (A) Carbon and silicon do not form any stable dihalides as germanium, tin or lead. This is because covalent bonds decrease in strength with increasing atomic size and the ionization energies for the heavier elements of the group are higher than expected due to a higher Zeff​, the relative stability of the +2 oxidation state increases smoothly from carbon to lead.

(B) The ability to form pπ−pπ multiple bonds among themselves decreases down the group. This type of π bonding is not strong for the heavier p-block elements.

(C) The tendency to catenate (to form chains of like atoms) decreases rapidly as we go down group 14 because bond energies for both the E–E and E–H bonds decrease with increasing atomic number. As a result of this trend, the thermal stability of catenated compounds decreases rapidly from carbon to lead.

(D) Carbon forms  CO and CO₂​ while other elements form MO₂​ except lead which forms PbO oxide.