Question

An element which is tetravalent and forms the basis of organic chemistry is:
A.Carbon
B.Hydrogen
C.Iron
D.Phosphorus

Answer 1

Hint: A tetravalent element makes four bonds available to form covalent chemical bonds. Organic chemistry mainly deals with hydrocarbons.

Complete step by step answer:
Organic chemistry is the branch of chemistry which deals with the hydrocarbons.
Carbon is the basis for Organic chemistry. It is a group 14 element having valence shell electronic configuration of \[n{s^2}n{p^2}\] . Carbon has the highest ability to bind with a variety of other elements and is tetravalent.

Hence the correct answer is (A) i.e Carbon.

Additional information:
Carbon is an essential constituent of all organic matter. Carbon having smallest atomic radius and lower molar volume among group 14 elements. It is nonmetal. It has a high melting and boiling point. Due to the absence of d orbitals it has least tendency to form complexes. It has high ionisation energy and is highly electronegative. Its maximum covalency remains 4. In C +4 oxidation has greater importance. It can form multiple bonds i.e, double bonds and triple bonds. The most important property is catenation. Catenation is the bonding of atoms of the same element into a series. Carbon and silicon are the nonmetals among group 14. Carbon is the essential constituent of most of the non-living materials including soils, rocks, hills etc. Carbon can form two similar oxides such as CO and \[C{O_2}\] . Carbon can form hydrides (eg. \[C{H_4},{C_2}{H_6},{C_2}{H_4},{C_2}{H_2}\] etc.) Allotropy is another property of carbon. It exists in two crystalline forms such as diamond and graphite. Coal, coke, charcoal, carbon black etc are the other allotropes of carbon. The catenation ability of group 14 elements decreases In the order \[C > Si > Ge > Sn > Pb\] .

Note:
The name carbon arises from the Latin word carbo. +4 is the common oxidation state of group 14 elements but +2 becomes more important for germanium, tin and lead. Due to high ionisation energy group 14 elements can’t form stable \[{M^{4 + }}\] ions. Carbon has the tendency to form \[{C_2}^{2 - }\] ions as in certain carbides. The last three elements of group 14 have the tendency to form both \[{M^{2 + }}\] and \[{M^{4 + }}\] .