Consider a neutral atom with 30 protons and 34 neutrons. The mass number for this atom is
mass number = #protons + # neutrons.
To find the mass number of an atom, you need to know the total number of protons and neutrons in its nucleus.
In this case, the atom has 30 protons and 34 neutrons. The mass number is the sum of these two values. So, to find the mass number, you can simply add 30 (number of protons) to 34 (number of neutrons).
Mass number = Protons + Neutrons
Mass number = 30 + 34 = 64
Therefore, the mass number for this atom is 64.