Final answer:
When calculating the binding energy, you would multiply z by the mass of a hydrogen atom (Zm(¹H)).
Step-by-step explanation:
The binding energy of a nucleus is calculated using the equation:
BE = (Am)c² = [(Zmp + Nmn) - mtot]c²
where mtot is the mass of the nuclide ^X, mp is the mass of a proton, and mn is the mass of a neutron.
Traditionally, we deal with the masses of neutral atoms. To get atomic masses into the equation, we add Z electrons to mtot to get m(AX), the atomic mass of the nuclide. We then add Z electrons to the Z protons, which gives Zm(¹H), or Z times the mass of a hydrogen atom.
Therefore, when calculating the binding energy, you would multiply z by the mass of a hydrogen atom (Zm(¹H)).