Question

In fission reactions, what causes the parent atom to divide in Different Proportions", for example Uranium divides into Barium and Krypton, why it does not divide into two atoms with same mass (118) or any other atoms other than `Ba` and `Kr` ?

Answer 1

it can divide into many products as experimentally 42 radioactive elements products have been discovers

Explanation:

First of all, the uranium in the fission reaction reaks due to the unstable heavy nucleus which cant hold the proton-proton interactions with
proton-neutron interactions

Secondly, your assumption of uranium breaking into krypton and barium is wrong it can break into any two atoms of similar mass and whose binding energy is near to after iron (since iron has maximum binding energy)