Fission of U-235 produces Cs-137 along with...? Question about Nuclear fission in general, here. If I have the fission of U-235 and I know that one of the products is Cs-137, is there a way of figuring out the other product? Should there be multiple possibilities? I understand that total number of Nucleons is preserved, but I'm supposing that I need to take into account that neutrons alone are also released? 
I'm almost certain that if I can work out the other product then I won't be able to know the isotope that it is, but can I even work out the atomic number of the other element? If so, how?
Many thanks
 A: Fission reaction produce a distribution of several different nuclei. Wikipedia (User:JWB) has a nice graph that shows the relative probabilities.
However, in the case of a single reaction, where it is given that a Cs-137 nucleus is produced, you can probably be more specific because there are correlations between the fission products, but it will require delving into the nuclear data - https://www-nds.iaea.org/
A: As indicated in the answer to this physics.stackexchange question the total amount of nucleons is preserved during fission.
As a result the atomic number of a daughter product can be predicted if another was already known. In the case of $U_{92}^{235}$ fissioning to $Cs_{55}^{137}$, we know the atomic number of the second fission product is given by:
$92=55+Z$, i.e. $Z=37$, which is the atomic nummber of Rb (rubidium).
Now as to the atomic weight of the Rb isotope, also use preservation of neutrons.
A $U_{92}^{235}$ nucleus contains $235-92=143$ neutrons and a $Cs_{55}^{137}$ nucleus contains $137-55=82$ neutrons. The difference is $143-82=61$ neutrons to be allocated.
Assume that $2$ to $4$ free neutrons also resulted from the fission then that leaves $57$ to $59$ neutrons for the Rb isotope so its atomic weight is probably $94$ to $98$.
A: Actually fission processes are stochastic, so we can't predict exact products of it. The most probable fission products are Cs-137 and Sr-90. The total amount of neutrons emitted is also quite unpredictable, but as I recall it usually lies in the range between 2 and 4. 
