Question

what represents the number of atoms present in one molecule of an element or a compound.​

Answer 1

Answer:

Atomicity is defined as the total number of atoms that constitute a molecule. For example, each molecule of oxygen (O2) is composed of two oxygen atoms. So atomicity of oxygen is 2.In older contexts, the term atomicity is sometimes used in the same sense as valency.

Answer 2

Answer:

Atomicity is defined as the total number of atoms that constitute a molecule. For example, each molecule of oxygen (O2) is composed of two oxygen atoms. So atomicity of oxygen is 2.[1]In older contexts, the term atomicity is sometimes used in the same sense as valency.All metals and some other elements, such as carbon, do not have a simple structure but consist of a very large and indefinite number of atoms bonded together. Their atomicity cannot be determined and is usually considered as 1.

Atomicity may vary in different allotropes of the same element.