Question

The atomicity of noble gases is:
(A) Diatomic
(B) Monoatomic
(C) Triatomic
(D) Tetraatomic

Answer 1

Atomicity can be defined as the number of atoms present in the molecule. Generally, atomicity is used in the cases of the molecular form of a particular element. Noble gases have complete octet in their valence shell electronic configuration.

Complete step by step solution:
We will first see what atomicity means.
- Atomicity can be defined as the number of atoms present in the molecule. Generally, atomicity is used in the cases of the molecular form of a particular element. That means that there is only one element present in the molecule. The number of atoms of the element may vary which defines the atomicity.
- Noble gases are the elements that are placed in that group-18 of the periodic table. The name noble gas is given to them because they do not react with other elements. They are not reactive because of their electronic configuration.
- The general electronic configuration of noble gases can be given as $n{s^2}n{p^6}$. That means that they have complete octet configuration in their valence shell. This gives them very high stability.
- Due to this high stability, the noble gas atoms do not combine with other atoms. So, they do not form bonds with any other atoms and hence they are always monoatomic.
- Monatomic gas is a gas which has only one atom in the structure.
- All the noble gases are monatomic. The examples include He (Helium), Ne (Neon), Ar (Argon), Xe (Xenon), Ra (Radon).
Thus, we can say that all the noble gases are monatomic.

So, the correct answer is option (B).

Note: Note that generally all noble gases do not react with any atoms but Xe is an exception in them. Xe can form certain complexes which are stable. The compounds of Xe include $XeO{F_4}$, $Xe{F_2}$, $Xe{O_4}$, etc.