Respuesta :
Thank you for posting your question here at brainly. I hope the answer will help you. Feel free to ask more questions.
Among the choices the phrase describes the decay modes and the half-lives of K-37 and K-42 is different decay modes and different half-lives
Among the choices the phrase describes the decay modes and the half-lives of K-37 and K-42 is different decay modes and different half-lives
Answer: (3) different decay modes and different half-lives
Explanation: Potassium-37 and Potassium-42 have the same number of protons but different numbers of neutrons i.e. they have same atomic number but different mass number. They are isotopes. Thus K-37 and K-42 have different decay modes
K-37 is positron decay and K-42 is beta decay.
[tex]_{19}^{37}{\textrm {Kr}}\rightarrow _{18}^{37}{\textrm {Ar}}+_{+1}^0{\textrm {e}}[/tex]
[tex]_{19}^{42}{\textrm {Kr}}\rightarrow _{20}^{42}{\textrm {Ca}}+_{-1}^0{\textrm {e}}[/tex]
K-37 has a half life of 1.23 seconds and K-42 has a half life of 12.4 hrs.
Thus they have different decay modes and different half lives.
