Determine the nuclear composition (number of protons and neutrons) of the following isotopes.
(a) vanadium-51 protons neutrons
(b) zinc-64 protons neutrons
(c) antimony-121 protons neutrons
(d) gadolinium-158 protons neutrons
(e) uranium-238 protons neutrons

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?