Question

The molecule having an atomicity of 4 is:
A.Sulphur molecule
B.Ozone molecule
C.Phosphorus molecule
D.Methane molecule

Answer 1

Atomicity refers to the number of atoms in a given molecule. Thus to solve this we need to know how many atoms are there in each of these molecules. Atoms of a molecule can be of same kind or different kind when we are considering the atomicity.

Complete answer:
To answer the question we have to look at the structure of each of the compounds and then decide which one is made up of 4 atoms.
Sulphur molecules usually exist in an 8 atom configuration. It is usually represented as ${S_8}$ and has a ring or crown shape structure.
The ozone molecule is an allotrope of oxygen that is very less stable and has the molecular formula of ${O_3}$ . It has a bent structure and its atomicity is 3
The phosphorus molecule in its white form is represented as ${P_4}$ and has a tetrahedral structure. Therefore its atomicity is 4.
Methane is the simplest organic molecule that has one carbon atom and 4 hydrogen atoms. It is represented as $C{H_4}$ and thus has an atomicity of 5.
From the above observations, we can say that the correct option is (C).

Note:
In questions like these, always use the method of elimination and find the answer. Here we could easily eliminate the options of having sulphur, ozone and methane because none of those molecules has 4 atoms in its molecule. This is easier to obtain the answer and will result in more accurate results.