Balance the nuclear reaction equation for the beta minus decay of iodine-131 by completing the missing numbers. es001-1.jpg the superscript of xenon is . the subscript of the electron is .

131            131            0
      I    →         Xe   +     e
  53             54           - 1

Explanation:

1) β decay is the radiactive process in which an element (Iodine - 131) in this case undergoes a desintegration by emitting beta radiation.

2) Beta radiation are electrons.

3) The electron has a negative charge 1-, and no mass (almost  not mass), so it is represented with a left supersript 0 (does not change the mass number) and a left underscript 1-  (the atomic number increases in 1).

4)  Then when iodine-131 emits a beta particle (electron) its mass number does not change, but the atomic number is increased from 53 to 54, becoming the isotope xenon - 131.

That is what the superscript to the left of Xe shows (131), while the subscript shows 54.

The subscript of electron is  - 1.

So the balance is:

Iodine              Xenon           electron

 131       =          131       +       0

   53       =            54       -         1