Explain the following observations using principles of nuclear chemistry:
(a) Gamma rays penetrate farther into the human body than alpha or beta rays.
(b) A nucleus actually weighs less than the sum of the masses of its neutrons and protons.
(c) Arsenic-81 is an unstable isotope of arsenic. What types of radioactive decay might it undergo?
(d) Small mass has enormous destructive power in a nuclear explosion.