a) Na-22 decays in two ways. In 100 atoms of Na-22 decaying, how many would decay by positron emission and how many would decay by electron capture? Why is the yield of photon gamma (+/-) so high?
b) In 100 decays of Ra-226, how many decays would result in emission of one photon, and how many decays would result in no photon emissions?
a) To determine how many atoms of Na-22 will decay by positron emission and how many will decay by electron capture, we need to look at the decay modes of Na-22.
1. Positron Emission: Na-22 undergoes positron emission by converting a proton into a neutron, thereby emitting a positron (a positively charged electron) and a neutrino. The resulting nucleus has an atomic number that is reduced by 1.
2. Electron Capture: Na-22 can also undergo electron capture, where an inner-shell electron combines with a proton in the nucleus, resulting in the emission of a neutrino. This conversion changes a proton into a neutron and reduces the atomic number by 1.
The yield of photon gamma (+/-) refers to the emission of gamma radiation during the decay process. The high yield of gamma photons is due to the energy difference between the initial and final atomic states. Gamma photons are high-energy photons emitted as a result of nuclear transitions, carrying away excess energy.
However, without additional information, we cannot determine the exact number of atoms decaying by positron emission or electron capture in 100 atoms of Na-22. The decay modes will depend on the particular circumstances of the sample and the half-lives of each decay pathway.
b) Ra-226 can decay through various pathways, such as alpha decay, beta decay, and gamma decay. To determine the number of decays resulting in the emission of one photon and the number of decays resulting in no photon emissions, we need more specific information about which decay pathway is being considered.
Without additional details, we cannot provide an accurate answer to this question. The number of decays resulting in one photon emission and no photon emission will depend on the specific decay pathways, excitation levels, and branching ratios associated with Ra-226's decay.