Question

How is Avogadro's hypothesis used to deduce atomicity of elementary gases?

Answer 1

Avogadro's hypothesis states that equal volume of all gases under similar conditions of temperature and pressure contain equal number of molecules. One of the applications of Avogadro’s law is to calculate the atomicity of elementary gases. It is defined as the number of atoms of elements present in one molecule of the substance. For example oxygen molecule has two oxygen atoms. So, atomicity of $O_2$ is 2. Similarly, atomicity of sulphur$S_8$ is 8.