The Atomic Mass Deficiency calculator computes the difference between the components of an atom (protons, neutrons and electrons) and the measure weight of the atom.
INSTRUCTION: Choose units and enter the following:
Mass Deficiency (Δm): The calculator returns the mass deficiency in atomic units, and the binding energy equivalent of that deficiency in mega electron volts (MeV). However this can be automatically converted to compatible units via the pull-down menu.
The Atomic Mass Deficiency1 calculates the difference between the measured mass of an atom and its calculated mass based on protons, neutrons, and electrons. Although electrons are sometimes discounted in the mass deficiency equation because of their very small mass, this equation includes them to ensure precise calculations. The difference in mass is accounted for by the binding energy in Einstein's famous E=mc2 equation.
The Atomic Mass Deficiency equation is:
Δm = (electrons + protons + neutrons) - actual mass of atom
Where:
[1] Whitten, et al. "Chemistry" 10th Edition. Pp. 854