Question

Which of the following is a polyatomic element?
(This question has multiple correct options.)
(A) Sulphur
(B) Phosphorus
(C) Argon
(D) Helium

Answer 1

To solve this question, we must first understand some basic concepts and differences about monoatomic, diatomic and polyatomic kind of species. Then we need to assess the properties of Polyatomic species and then check among the given options that which of the following is/are polyatomic species and then only we can conclude the correct answer.

Complete step-by-step answer: Before we move forward with the solution of this given question, let us first understand some basic concepts: Atomicity is defined as the total number of atoms that constitute a molecule. Now let's find out what is the meaning for each of them:
Monatomic: Monoatomic is a combination of two words “mono” and “atomic” means single atom. This term is applied to the gases as a monatomic gas. In the gaseous phase at sufficiently high temperatures, all the chemical elements are monatomic gases.e.g. $He,{\text{ }}Ne,{\text{ }}Ar$ (all noble gases are monatomic)
Diatomic: Diatomic molecules are those molecules that are composed of only two atoms. If a diatomic molecule is composed of the same element; it is known as a homonuclear and if it is composed of two different elements is known as heteronuclear. Ex- ${H_2}\,,\,{N_2}\,,\,{O_2}$
Polyatomic: The elements that have more than two atoms bonded by a covalent bond are referred to as polyatomic elements. Ex- ${P_4}\,,\,{S_8}\,,\,Cl{O_2}^ -$
So clearly, after going through the above explanation we can conclude that:Sulphur $({S_8})$ and phosphorus $({P_4})$ are polyatomic elements. Whereas options C and D are noble gases or are monatomic elements.

So, clearly we can conclude that the correct answer is Option (A) and (B).

b>Note:**All metals and some other elements (such as carbon), do not have a simple structure but consist of a very large number of atoms bonded together. Their atomicity cannot be determined and is usually considered as $1$ .