Question

how we can know atomicity of all elements ??

Answer 1

It can be determined as a ratio of molecular mass and atomic mass. For example, using the case of oxygen molecule, the molecular mass is 32 (= 2x16), while the atomic mass is 16. If we divide the two, we get atomicityas 2 (=32/16). We can use this relation tofind the atomicity of any other elements as well.