Question

The more readily fissionable isotope of uranium has an atomic mass of:

• A. 234
• B. 235
• C. 236
• D. 238

Answer 1

The correct option is B 235

Uranium-235 ( ${}^{235}U$ ) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a fission chain reaction. It is the only fissile isotope found in significant quantity in nature.