Question

Atomic number is considered to be a more appropriate parameter than atomic mass for classification of elements in a periodic table. why? (5 marks)

Answer 1

The physical and chemical properties of an atom depends upon the number of proton present in the nucleus and the number of electron present around the nucleus. This was proved by Mosley by its experiment in which direct relation is derived between frequency of incident light and atomic number of an atom. Therefore atomic number is considered as most appropriate for arrangement of element in periodic table.
We know that atomic number gives us the number of protons in the nucleus of an atom. Atomic number increases by one in going from one element to the next but atomic mass does not vary regularly from element to element. Atomic number of every element is fixed. That is why atomic number is considered to be a more appropriate parameter for the classification of elements than atomic number