Question

Atomic mass number of an element is `232` and its atomic number is `90`. The end product of this radiaoctive element is an isotope of lead (atomic mass `208` and atomic number `82`.) The number of `alpha`-and `beta` -particles emitted are.
A. `alpha = 3, beta = 3`
B. `alpha = 3, beta = 4`
C. `alpha = 6, beta = 0`
D. `alpha = 4, beta = 6`.

Answer 1

Correct Answer - B
(b) Number of `alpha-`particles emitted `= (232 - 208)/(4) = 6`
Decrease in charge number due to `alpha-`emission `= 12`
But decrease in charge number `=(90 - 82)` i.e., `8`
Clearly, `4 beta-`particles are emitted.