Can you please explain why the actual atomic mass is greater than mass number?
Mass number = number of protons + number of neutrons in an atom.
Now, mass of protons and neutrons is measured in daltons or atomic mass unit,u but the mass of each neutron and proton is slightly greater than 1 dalton, so actual atomic mass is slightly greater than mass number.
Example: mass umber of calcium = 20 + 20 = 40 u
Actual atomic mass of calcium = 40.078 u
Now, mass of protons and neutrons is measured in daltons or atomic mass unit,u but the mass of each neutron and proton is slightly greater than 1 dalton, so actual atomic mass is slightly greater than mass number.
Example: mass umber of calcium = 20 + 20 = 40 u
Actual atomic mass of calcium = 40.078 u