Question

The atomicity of a noble gas is:
A) 2
B)1
C) 0
D) 6

Answer 1

We know that atomicity is the total number of atoms present in one molecule of an element, compound, or a substance. Like atomicity of water is 3, because 2 hydrogen atoms and 1 oxygen atom whose sum is three, so atomicity is three of water.

Complete answer:

There are four types of atomicity, monatomic, diatomic, triatomic, tetratomic.
If the molecule of many elements formed by an only single atom of that element, known as monatomic. For example, Ar, He, they contain one atomicity. On the other hand, if the molecule formed by two atoms of that element, known as diatomic. For example, oxygen. The molecules of many elements are formed through the three atoms of that element, known as triatomic. For example ${{\rm{O}}_{\rm{3}}}$,${\rm{C}}{{\rm{O}}_{\rm{2}}}$. If the molecule of many elements is formed by four atoms of that element, known as tetratomic. For example ${{\rm{P}}_{\rm{4}}}$,${\rm{S}}{{\rm{O}}_{\rm{3}}}$.
Noble gases are monatomic because they have complete octets apart from Helium, which has duet, they have zero valence. The capacity to either gain or accept electrons is zero. Hence, they are highly stable on their own and do not react with others to form compounds in standard temperature and pressure.

Therefore, the correct answer is B.

Note: Noble gases can be liquefied very easily however, it is difficult to liquefy noble gases as their atoms are held by weak Vander Waals forces and they remain as liquid over only a small temperature range. Liquefaction of gases can be brought about by complex processes involving various compressions and expansions to achieve high pressure and very low temperature.