Consider a neutral atom with 30 protons and 34 neutrons. The mass number for this atom is

was

To determine the mass number of an atom, you need to add together the number of protons and the number of neutrons.

In this case, the atom has 30 protons and 34 neutrons. To find the mass number, add these two together:

30 protons + 34 neutrons = 64

Therefore, the mass number for this atom is 64.