Physics - Modern Physics Question with Solution | TestHub

According to conservation of mass number $$10+4=13+1$$ According to conservation of charge number, $5+2\ne 7+1$ Hence (1) is not possible. According to conservation of charge number, $93=94-1$ According to conservation of mass number, $239=239$ Hence (3) is possible. According to conservation of mass number, $11+1=12$ According to conservation of charge number, $7+1\ne 6-1$ Hence (4) is not possible. ${}_{11}^{23}\mathrm{Na}+{}_1^1\mathrm{H}$ also satisfies both the conservation of mass number and charge. However, ${}^{23}\mathrm{Na}$ is a very stable isotope and nuclear reaction will be very difficult. The formation of $\mathrm{Pu}$ from $\mathrm{Np}$ is well known. It satisfies the conditions of conservations and $\mathrm{Np}$ is also very unstable. Therefore (3) is the only correct answer.