The compound unstabel nucleus `._(92)^(236)U` often decays in accordance with the following reaction
`_(92)^(236)U rarr ._(54)^(140)Xe +`_(38)^(94)Sr ` + other particles
During the reaction, the uranium nucleus ''fissions'' (splits) into the two smaller nuceli have higher nuclear binding energy per nucleon (although the lighter nuclei have lower total nuclear binding energies, because they contain fewer nucleons).
Inside a nucleus, the nucleons (protonsa and neutrons)attract each other with a ''strong nuclear'' force. All neutrons exert approxiamtely the same strong nuclear force on each other. This force holds the nuclear are very close together at intranuclear distances.
In the nuclear reaction presented above, the ''otter particles'' might be .

Options

A. An alpha particle, which consists of two protons and two neutrons
B. two protons
C. one proton and one neutron
D. two neutrons

Answer

d

Explanation

Nuclear ractions conserve total charge and also conserve the total approximate mass (as measured by the atomic mass number). Therefore, since the uranium, xenon, and strontium nuclei have atomic `236,140` and `94`, the 'other particles' must have total atomic mass `A` such that
`236 =140+94+A`
So, `A=2`. The other particles are two nucleons. This narrows down the answer to options (b), ( c) and (d). For nuclei, the atomic number `--i.e.`, the number of protons --tells us the charge. So, the other particles must have total charge `Z` such that
`92 =54+38+Z` or `Z=0`
In summary, the other particles have total atomic mass `2` and total charge `0`. Only option (d) fits this description.