Question

The total number of electrons in one molecule of carbon dioxide is:
A.22
B.44
C.66
D.88

Answer 1

Valence theory and chemical bonding model explains about the number of electrons present in one molecule of carbon dioxide. They consider that the overlapping atomic orbitals of the participating atoms form a bond between the atoms and due to this, it is most likely that electrons must be available in that region.

Complete step by step answer:
Carbon dioxide has the chemical formula $C{O_2}$ and it is a linear molecule having a central carbon atom joined by two pairs of double bonds to the oxygen atoms. We can represent it as O = C = O. Carbon dioxide is a colourless gas at room temperature and has a slightly sweet smell.
Valence bond theory explains the structure and bonding of carbon dioxide molecules. It views bonds as weakly coupled orbitals which have small overlapping. There is no gain or loss of electrons during formation of this molecule. Electrons are shared between carbon and oxygen atoms so as to form a covalent bond between them. This is further shown in the Lewis dot structure.

We can count the number of electrons of both carbon and two oxygen atoms to get the total number of electrons in carbon dioxide. For this, we are supposed to write the electronic configuration of both. Here are the electronic configurations:

$$C:1{s^2}2{s^2}2{p^2} \\\ O:1{s^2}2{s^2}2{p^4} \\\$$

From this, we can see that there are six electrons in one carbon atom and eight electrons in one oxygen atom. So, there will be a total 16 electrons from two oxygen atoms. Thus, the total number of electrons are 6+8+8=22.
$C + 2(O) \to C{O_2}$

Hence, the correct option is (A).
Note:
Lewis structures are diagrams that show the bonding between atoms of a molecule and the non-bonding pairs of electrons which might exist in the molecules. These structures were used to determine the type of bond and number of electrons gained or lost during the formation of a molecule. But nowadays, modern theories are used to describe the same.