$\beta$-emission is always accompanied by

$A$ radioisotope will not emit

The number of $\alpha$ and $\beta$-particles emitted in the nuclear reaction $_{92}U^{238} \to _{90}Th^{234} \to _{91}Pa^{234}$ are respectively:

After the emission of a $\beta$-particle followed by an $\alpha$-particle from ${ }_{83}^{214} Bi$, the number of neutrons in the resulting atom is:

An atom has a mass number of $232$ and an atomic number of $90$. How many $\alpha$-particles should it emit after the emission of two $\beta$-particles,so that the resulting atom has a mass number of $212$ and an atomic number of $82$?

The substance used in cancer therapy is