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.

Options

A. `6,3`
B. `6,4`
C. `5,5`
D. `4,6`

Answer

b

Explanation

Decreases in mass number `=232 -208 =24`
Number of `alpha`-particles emitted `=(24)/(4=6)`
Due to emission of 6 particles, decreases in charge number is `12`. But actual decrease in number is `8`. Clearly, 4 `beta`- particles are emitted.