Correct Answer - Option 2 : C > Si > Ge ≈ Sn
Concept:
Carbon is a chemical element with the symbol C and atomic number 6. It is non-metallic and tetravalent making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Three isotopes occur naturally, and being stable.
Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard and brittle crystalline solid with a blue-grey metallic cluster, and it is a tetravalent metalloid and semiconductor. It is relatively unreactive.
Germanium is a chemical element with the symbol Ge and atomic number 32. It is a lustrous, hard-brittle, greyish-white metalloid in the carbon group, chemically similar to its group neighbour’s silicon and tin. Pure germanium is a semiconductor with an appearance similar to elemental silicon.
Tin is a chemical element with the symbol Sn and atomic number 50. Tin is a silvery metal that characteristic has a faint yellow hue like indium, tin is soft enough to be cut without much force. When a bar of tin is bent the so-called "tin cry" can be heard as a result of sliding tin crystals reforming this trait is shared by indium cadmium and frozen mercury.
The catenation property among 14th group elements is based on bond enthalpy value of bond between the same elements.
Bond enthalpy is also known as bond energy which is defined as the amount of energy required to break one mole of the stated bond.
The decreasing order of bond enthalpy value is
C – C > Si > Si > Ge > Ge ≈ Sn – Sn in KJ/mol
∴ Decreasing order of catenation is C > Si > Ge ≈ Sn.
