When a radium atom,which is placed in group $II$,loses an $\alpha$-particle,a new element is formed which should be placed in group ........

$A$ radioactive substance ${}_{88}X^{228}$ (Group $IIA$) emits $3 \alpha$ and $3 \beta$ particles to form $Y$. To which group of the long form of the periodic table does $Y$ belong?

$_{84}Po^{210} \xrightarrow{} _{82}Pb^{206} + _{2}He^{4}$. From the above equation,deduce the position of polonium in the periodic table (lead belongs to group $IV A$).

Whenever the parent nucleus emits a $\beta^{-}$ particle,the daughter element is shifted in the periodic table:

Emission of a $\beta$-particle by an atom of an element results in the formation of its