Question

List the symmetry elements of $C{H_3}Cl$ ?

Answer 1

In order to answer this question, we should know the structure of the molecule given i.e. $C{H_3}Cl$ . Also, this question is based upon the concept related to group theory that include symmetry operation and their symmetry elements.

Complete answer:
Let us first understand the symmetry element. A symmetry element is termed as a reference point form where the symmetry operations take place. In other words, we can say that symmetry operation is a geometrical entity that can be point, axis or plane and from the symmetry operation is performed. Now, a symmetry operation is the movement of a molecule such that the molecules appear the same as before.
For the given question, just imagine the structure of $C{H_3}Cl$ . Here, in this molecule, the central atom is carbon and it has four bonds i.e. three bonds with hydrogen and one bond with chlorine. The bond angle of these molecules is ${109.4^o}$ which indicates that it is tetrahedral in shape.
Let’s come to the question, we have to predict the symmetry element of the molecule.
$C{H_3}Cl$ belongs to the ${C_{3V}}$ point group.
It has the symmetry element $E$ , ${C_3}$ axis and three ${\sigma _v}$ planes. The molecule has a ${C_3}$ axis that includes the $C - Cl$ bond. The plane of the molecules includes a $Cl - C - H$ bond.
Also, it has three mirror planes.
Therefore, the $C{H_3}Cl$ has the symmetry elements $E$ , ${C_3}$ axis and ${\sigma _v}$ planes.

Note:
Group theory helps in simplifying the problems that arise in molecular spectroscopy. This theory does not make any quantitative predictions. For answering the problem related to symmetry elements and their operations, we should know about the structure of the molecule given.