Consider the nuclear reaction 2814 Si + 2814 Mg + X where X is a nuclide. (a)

Question:

Consider the nuclear reaction 2814 Si + γ → 2814 Mg + X where X is a nuclide.
(a) What is Z and A for the nuclide X?
(b) Ignoring the effects of recoil, what minimum energy must the photon have for this reaction to occur? The mass of a 2814Si atom is 27.976927 u, and the mass of a 2812Mg atom is 23.985042 u.