Question

Which of the following isotopes would most likely be unstable and therefore radioactive?

Answer 1

Answer: Mercury-194 is an unstable isotope and hence is radioactive.

Explanation: Mercury-194 is an isotope of mercury, having formula $_{80}^{194}\textrm{Hg}$

Number of protons in this isotope = 80

Number of neutrons in this isotope = 114

This isotope is radioactive in nature and under decay process by Electron Capture.

Electron capture reactions are the reactions in which a proton in a nucleus absorbs an electron and convert it into neutron. The resulting nucleus will have a decreased atomic number and same atomic mass.

Reaction for electron capture of mercury-194 follows:

$_{80}^{194}\textrm{Hg}+_{-1}^0\textrm{e}\rightarrow _{79}^{194}\textrm{Au}$