Uranium-238 captures a neutron and the product subsequently undergoes two β⁻-decays, following the sequence ²³⁸₉₂U + n → ²³⁹₉₂U → ²³⁹₉₃Np → ²³⁹₉₄Pu. Which statement about this sequence is correct?
Options

Question

Uranium-238 captures a neutron and the product subsequently undergoes two β⁻-decays, following the sequence ²³⁸₉₂U + n → ²³⁹₉₂U → ²³⁹₉₃Np → ²³⁹₉₄Pu. Which statement about this sequence is correct?

Options

G1 Physics · Accepted Answer

Neutron capture changes A: 238 → 239 while Z remains 92. In each β⁻-decay, a neutron converts into a proton: n → p + e⁻ + ν̄ₑ. Therefore the mass number remains 239, while the atomic number increases by 1 in each β⁻-decay: 92 → 93 → 94. Thus the sequence produces ²³⁹₉₄Pu. Correct option: A.