predict a likely mode of decay for each of the following unstable nuclides. Explain why.
1.) Mo-109
2.) Fr-202
3.) Rn-196
4.) Sb-132
5.) P-27
6.) Ru-90
To predict the likely mode of decay for each unstable nuclide, we need to consider the stability of their nuclei and the relative strength of various decay processes. The most common types of radioactive decay include alpha decay, beta decay, gamma decay, and electron capture.
1.) Mo-109: The nuclide Mo-109 has a relatively high atomic number, suggesting it may undergo beta decay. In beta decay, a neutron in the nucleus is converted into a proton, emitting a high-energy electron (beta particle) and an antineutrino. Therefore, Mo-109 is likely to undergo beta decay.
2.) Fr-202: Francium-202 is a highly unstable nuclide with a large atomic number. Such heavy nuclides often undergo alpha decay due to their weak binding forces. Therefore, Fr-202 is likely to decay via alpha decay, emitting an alpha particle (helium nucleus).
3.) Rn-196: Radon-196 is an isotope of radon that is not commonly observed. It is an odd-odd nucleus, meaning both its atomic and mass numbers are odd. Odd-odd nuclides often decay via beta decay, where one neutron is converted into a proton and a high-energy electron (beta particle) and antineutrino are emitted. Therefore, Rn-196 is likely to undergo beta decay.
4.) Sb-132: Antimony-132 has a relatively high atomic number, making it a good candidate for beta decay. However, it is also close to the neutron-drip line, indicating it may undergo neutron emission. Neutron emission is analogous to beta decay, but instead of a neutron being converted into a proton and electron, a neutron is simply emitted. Therefore, Sb-132 may decay through neutron emission.
5.) P-27: Phosphorus-27 has a low atomic number and tends to be closer to stability compared to other unstable nuclides. It is likely to decay via positron emission. Positron emission is a type of beta decay where a proton is converted into a neutron, emitting a positron (a positively charged electron) and a neutrino.
6.) Ru-90: Ruthenium-90 is an isotope of ruthenium that lacks stability due to an excess of neutrons. It is likely to undergo beta decay to increase the neutron-to-proton ratio. Therefore, Ru-90 is likely to decay via beta decay.