Question

what is difference between atomic mass and mass number of the elements?

Answer 1

Hi....

Atomic number is the no of protons or electrons in an atom....
&
Atomic mass no is the sum of total no of protons and neutrons in an atom...

Hope this helps you.... ☺

Answer 2

Mass number of an element is the number of protons+neutrons in that atom.

Atomic mass is the number of protons/electrons present in that atom.

For example,  atomic mass of oxygen is 8 ( no of protons) and it's mas number is 16 ( 8 protons + 8 neutrons)

Hope this helps!