Question

Valency of carbon is 44, from this we understand that there are ______ chemical bond(s) between the carbon atom and one oxygen atom in the compound carbon dioxide.
(A) 1
(B) 2
(C) 3
(D) 4

Answer 1

Hint: Here, you are given a compound which is carbon dioxide and valency of carbon to be 4, you are asked to find the number of chemical bonds that are formed in the compound carbon dioxide between the carbon atom and one oxygen atom. In order to answer this question, you need to look at the electronic configuration of both carbon and oxygen and try figuring out how much bonds can carbon make with a single oxygen atom. Also, another method to find the number of chemical bonds is to know the hybridization of the carbon atom.

Complete step by step solution:
Let us have a look at the electronic configuration of both the elements, carbon and oxygen.
Electronic configuration of carbon is $1s^2$, $2s^2$, $2p^2$
Electronic configuration of oxygen is $1s^2$, $2s^2$, $2p^4$
Number of valence electrons in the carbon atom as you can see is 4 and that in oxygen is 6. Here, carbon can make 4 bonds as it has 4 valence electrons but oxygen can make only 2 bonds due to its high electronegativity and small size. Carbon dioxide is a stable compound and for it to be stable, the carbon will make four bonds with oxygen and each oxygen has to make two bonds with carbon. You can see that the only way to make a stable and symmetric compound is that carbon makes double bonds with each of the oxygen atoms.
Therefore, there are 2 chemical bonds between the carbon atom and one oxygen atom in the compound carbon dioxide.
Option (B) is correct.

Note :
Remember that the valency of carbon is 4 and hence it is capable of making 4 chemical bonds but in case of oxygen, its valency is 6 but it can only make 2 chemical bonds, reason being its size and electronegativity. Also remember that the carbon makes double bonds with each oxygen and the oxygen electrons participating in the bond are the electrons from the lone pair.