A nucleus with $Z = 92$ emits the following in a sequence: $\alpha ,\,{\beta ^ - },\,{\beta ^ - },\,\alpha ,\alpha ,\alpha ,\alpha ,\alpha ,{\beta ^ - },\,{\beta ^ - },\alpha ,\,{\beta ^ + },\,{\beta ^ + },\,\alpha $. The $Z$ of the resulting nucleus is
$74$
$76$
$78$
$82$
Assertion: ${}_Z{X^A}$ undergoes a $2\alpha -$ decays, $2\beta -$ decays and $2\gamma - $ decays and the daughter product is ${}_{Z - 2}{X^{A - 8}}$
Reason : In $\alpha - $decays the mass number decreases by $4$ and atomic number decreases by $2$. In $2\beta - $ decays the mass number remains unchanged, but atomic number increases by $1$ only.
When a nucleus with atomic number $Z$ and mass number $A$ undergoes a radioactive decay process :
The composition of an $\alpha $- particle can be expressed as
In a radioactive decay chain, the initial nucleus is ${}_{90}^{232}Th$. At the end there are $6\,\,\alpha -$ particles and $4\,\,\beta -$ particles with are emitted. If the end nucleus is ${}_Z^AX\,,\,A$ and $Z$ are given by
A nucleus of atomic mass $A$ and atomic number $Z$ emits ${M_1}$ particles. The atomic mass and atomic number of the resulting nucleus are