Physics

Problem

_{94}^{239}\text{Pu}

undergoes the following decay chain in order:

\alpha

\beta^{-}

\beta^{-}

\alpha

\beta^{+}

. Which isotope is formed after the final decay? a)

_{92}^{235}\text{U}

_{91}^{231}\text{Pa}

_{92}^{231}\text{U}

_{93}^{231}\text{Np}