An element $A$ decays into element $C$ by a two step process :
$A \to B + {\;_2}H{e^4}$
$B \to C + \;2{e^ - }$
Then
$A$ and $C$ are isotopes
$A$ and $C$ are isobars
$A$ and $B$ are isotopes
$A$ and $B$ are isobars
When a radioactive substance emits an $\alpha$- particle, its position in the periodic table is lowered by
An artificial radioactive decay series begins with unstable $_{94}^{241}Pu$. The stable nuclide obtained after eight $\alpha - $ decays and five $\beta - $ decays is
In the given nuclear reaction, the element $X$ is :
${ }_{11}^{22} Na \rightarrow X + e ^{+}+v$
A neutron strikes a ${ }_{92} U ^{235}$ nucleus and as a result ${ }_{38} Kr ^{93}$ and ${ }_{56} Ba ^{140}$ are produced with
In the nuclear reaction: $X(n,\,\alpha ){\,_3}L{i^7}$ the term $X$ will be