Answer
Yes, mass excess of an alpha particle will be lesser than the particle's total binding energy.
Work Step by Step
1. First of all, the excess mass of a nuclide is the difference between actual mass and the mass number (A). From the plot Fig. 42-13, one could see by projecting Z=2 and N=2 (for alpha particle), the mass excess will be around 2.4 MeV in energy equivalent.
2. Binding energy of the alpha particle is the amount of energy required to remove 2 protons and 2 neutrons from the alpha particle, which will be around 7 MeV/A ( can be seen from fig. 42-7) and total binding energy will be 28 MeV for alpha particle.
That's why it is very stable nucleus in its neighbourhood.
