Question

explain atomic mass qnd gram atomic mass. why does mass have different expression viz: u and gm

Answer 1

atomic mass of an element is defined as 1/12 of mass of carbon 12 atom
1u = 1/12mass of carbon 12 atom

to calcute atomic mass formula is
for even number multiply by 2
for odd number multiply by 2 then add one(except nitrogen and chlorine)
in gram atomic mass you simply remove u and add g only this