Answer:
The atomic mass of iodine-131 is 130.9056485 amu.
Explanation:
Beta-decay is the process in which a neutron gets converted into a proton and an electron releasing a beta-particle. The beta particle released carries a charge of -1 units.
[tex]_Z^A\textrm{X}\rightarrow _{Z+1}^A\textrm{Y}+_{-1}^0\beta[/tex]
[tex]_{53}^{131}\textrm{I}\rightarrow _{54}^{131}\textrm{Xe}+_{-1}^0\beta[/tex]
Energy released during beta particle emission = E
[tex]E=\Delta mc^2[/tex]
[tex]1.5541\times 10^{-33} J=\Delta m(3\times 10^8 m/s)^2[/tex]
[tex]\Delta m=1.7267\times 10^{-50} kg[/tex]
[tex]\Delta m=1.0399\times 10^{-23} amu[/tex]
Mass of reactant = Mass of product + Δm
= Mass of beta particle + nuclide + Δm
Mass Beta-particle =[tex]9.10938291\times 10^{-31} kg=0.000548579 amu[/tex]
Mass of reactant =
=130.9051+0.000548579 amu +[tex]1.0399\times 10^{-23}[/tex] amu
= 130.9056485 amu
The atomic mass of iodine-131 is 130.9056485 amu.
