Question

The α decay of a nucleus near mass 200 has two components of energies 4.687 and 4.650MeV. Neither populates the ground state of the daughter, but each is followed by a γ ray, of respective energy 266 and 305 The gamma rays are measured in keV and no other rays are seen. From this, what will the two nuclei be? 1) Even-even 2) Odd-odd 3) Odd-even 4) Even-odd

Answer 1

The question asks about the nature of nuclei based on alpha decay and subsequent gamma ray emissions. Since alpha decay emits a 4He nucleus and the gamma rays don't change the number of protons or neutrons, we can't conclusively determine the nature of the parent nuclei from the given data alone.

Step-by-step explanation:

The student's question concerns the identification of nuclei characteristics based on alpha decay energy components and their subsequent gamma radiation. In alpha decay, a parent nucleus emits a 4He nucleus, resulting in a daughter nucleus with two fewer protons and two fewer neutrons than the parent. Since the energy components of the alpha decay are different and neither results in the daughter nucleus being in its ground state, but instead each is followed by a distinct energy gamma ray, it suggests the presence of excited states and the possibility of multiple energy levels in the daughter nuclei.

The fact that the gamma rays are of different energies (266 keV and 305 keV) indicates that there are at least two excited states of the daughter nucleus, with the alpha decay transitioning to these states rather than to the ground state. These excited states then release energy in the form of gamma rays as they transition to a lower energy state. Because the gamma rays do not change the number of protons or neutrons, they do not affect the charge (Z) or mass number (A) of the daughter nucleus.

Regarding the possible categorization of the parent nuclei, we know that if a nucleus is even-even (meaning both the number of protons and the number of neutrons are even), its decay will lead to a daughter nucleus that is even-even or odd-odd since the alpha particle contains even numbers of both protons and neutrons. Similarly, if a parent nucleus is odd-even or even-odd, it will result in a daughter nucleus of type odd-odd or even-even, respectively. Thus, without additional information specific to the parent nuclei, we cannot conclude the exact nature of the nuclei based only on the provided alpha decay and gamma radiation data.