Question

Catenation properties of C, Si, Ge, Sn, Pb are in order:
(A) $ C > > Si > Ge \approx Sn > > Pb $
(B) $ C < Si < Ge < Sn < Pb $
(C) $ C > Si > Sn > Ge > Pb $
(D) None of the above

Answer 1

Hint: To answer this question, you must recall the concept of catenation. Catenation is the property of formation of long chains formed by the atoms of the same element. Carbon is known to have catenation due to its small size and tetravalency.

Complete step by step solution
We have to find the order of the tendency of formation of long chains in group 14 elements. Carbon is the first element of the group 14 and thus it has no d- orbitals available. As a result carbon is small in size and cannot form complexes. It has a tendency to bind with fellow carbon atoms and form long chains. This property is known as catenation and is responsible for carbon being the essential constituent of the majority of organic compounds.
As we go down the group, the strength of bonding decreases as the size of the atoms increases and thus the tendency for catenation decreases. The order of the catenation is:
 $ C > > Si > Ge \approx Sn > > Pb $
The correct answer is A.

Note:
The basis for organic chemistry is carbon. It forms the backbone of all organic compounds due to the high stability of the carbon- carbon bond. Carbon has an atomic number 6 and it is present in the group 14 of the modern periodic table. It has four valence electrons in its valence shell, 2 in the s- orbital and 2 in the p- orbital. One electron from the s- orbital is excited to the p- orbital and thus, the valency is extended to 4 due to the presence of four unpaired electrons. Due to its tetravalency, carbon has the tendency to bond to a number of elements and form a variety of compounds.