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