Question

what is meant by atomic mass, gram atomic mass of an element? Why is the mass have different expressions i.e, 'u' and 'g'

Answer 1

The atomic mass of an atom of an element is expressed in atomic mass unit and may be defined as the total number of protons and neutrons present on that element.
The gram atomic mass is defined as the amount of substance in gram and it is numerically equal to its atomic mass
'u' and 'g' are the symbols used to represent the unit of gram atomic mass. example, the gram atomic mass of carbon is 24u or 24g.Both the symbolscan be use to represent gram atomic mass.

Answer 2

the quantity is same but the only difference is that if we have gram atomic mass then it will be written with its unit igram but if it is only written atomic mass then its unit will be you