Physics - Modern Physics Question with Solution | TestHub

(i) When$\alpha$-particle is emitted from a radioactive nucleus then atomic number decreases by$2$and atomic mass decreases by$4$.

(ii) When$\beta$-particle emitted from a radioactive nucleus then atomic number is increased by$1$and atomic mass unaffected.

Here, atomic number$\left(Z\right)=92$

After emitting$8 \alpha$-particles and$6\beta$-particles,

$Z=92-2\times 8+6=82$

and atomic mass,$A=238$

$\therefore A=238-4\times 8=206$