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Ruthenium-106 (106Ru) is used to treat melanoma in the eye. This isotope decays

ID: 1384391 • Letter: R

Question

Ruthenium-106 (106Ru) is used to treat melanoma in the eye. This isotope decays by beta - emission with a half-life of 373.59 days. One source of the isotope is reprocessed nuclear reactor fuel. How many protons and neutrons does the 106Ru nucleus contain? Identify the missing daughter nucleus in the beta - emission decay of 106Ru below. Tip: If you need to clear your work and reset the question marks, click the icon that looks like two red arrows in the menu below the box. How many years after 106Ru is implanted in the eye does it take for its decay rate (or activity) to be reduced to 21.5% of the initial decay rate? Use 1 year = 365 days.

Explanation / Answer

part a)

durin beta (-) emission the atomi number number increase by 1 and the mass number remains same


number of protons = 45   neutrons = 106-44 = 62


part b)


? = Rh106

part c)

given T(1/2) = 373.59 days


T(1/2) = 0.693/?


? = 0.693/373.59 = 1.86e-3 /day

activity = A = Ao*e^-t?


A = 21.5% Ao

0.215 = e^-t*1.86e-3


e^t*1.86e-3 = 1/0.215 = 4.65

t*1.86e-3 = 4.65


t = 2500 days

t = 2500/365 = 6.85 years