Explanation:
First off, it is important to know the type of decay that Iodine undergo to give Xenon.
This is achieved by comparing the mass number and atomic number of the products and reactants.
Iodine
Mass Number = 137
Atomic Number = 53
Xenon
Mass Number = 137
Atomic Number = 54
Upon comparison, we can tell that the only change is the increase in the atomic numbers.
Due to this, we now know it is a beta decay. In beta decay, one of the neutrons in the nucleus suddenly changes into a proton, causing an increase in the atomic number of an element.
In a balanced nuclear equation, the sum of the mass numbers on the reactant side must equal the sum of the mass numbers on the product side. The same must be true for the atomic numbers.
Reactant side;
Mass number = 137
Atomic Number = 53
Product side;
Mass number = 137 +0 = 137
Atomic Number = 54 + (-1) = 53
The equation is given in the attachment.
