Question

What is the valency of the carbon in \[C{{H}_{4}}\]?
A. 1
B. 3
C. 4
D. 6

Answer 1

Hint: We know that valency is the number of electrons in the outermost shell of a particular element. And carbon is from the 2nd period and 14th group and it has 6 electrons.

Complete step-by-step answer:
Valency of an atom never changes, it is a constant term. It does not depend on the other atom to which it is bonded. We know that configuration of carbon is \[1{{s}^{2}}2{{s}^{2}}2{{p}^{2}}\].
Carbon requires 4 more electrons to gain the configuration of stable inert gas or to complete its octet or 4 electrons should be removed for this purpose.
Valency has nothing to do with bonding. The thing which changes with bonding is oxidation state. And the oxidation state is the number of electrons that an element in a particular compound has lost or gained. For example in \[C{{H}_{4}}\] O.S. of carbon is 4 and in \[{{C}_{2}}{{H}_{6}}\] it is 3.
Methane has its molecular formula \[C{{H}_{4}}\] . It is formed by one carbon atom and four hydrogen atoms . Hydrogen has its valency 1 and carbon being tetravalent needs four valence electrons to acquire noble gas configuration, where it shares its 4 electrons with four hydrogen atoms. Therefore, the valency of carbon atoms in methane is 4.
So, from the above points conclusion is that the valency of carbon is 4.
Then the correct answer is “C”.

Note: We should know that valency and oxidation state are two different things. If double or triple bonds are made by carbon it does not change its valency.