Answer
$^{95}Y$
Work Step by Step
The equation provided to us is
$^{233} \mathrm{U}+\mathrm{n} \rightarrow \mathrm{X}+\mathrm{Y}+b \mathrm{n}$
In this equation we are given that
X = $^{139}$I and b = 2
$\therefore$ Our equation becomes
$^{233} \mathrm{U}+\mathrm{n} \rightarrow \mathrm{^{139}I}+\mathrm{Y}+ 2\mathrm{n}$
And now we have to find Y
For our calculations,
We should remember that
For neutron Z = 0 & A = 1
For Uranium Z = 92
In this case, Iodine has Z = 53
In such equations, Mass numbers & Z must be balanced to ensure that there is no mass loss on either side,
Therefore, Z for "Y" will be 92-53 = 39
Yttrium has Z = 39
$\therefore$ Y must be Yttrium
For A;
235+1-39 = 95
$\therefore$ Y = $^{95}Y$
