Atomic mass number of an element is `232` and its atomic number is `90`. The end product of this radioactive element is an isotope of lead (atomic mass `208` and atomic number `82`.) The number of `alpha`-and `beta` -particles emitted are.

Options

A. `alpha=3,beta=3`
B. `alpha=6,beta=4`
C. `alpha=6,beta=0`
D. `alpha=4,beta=6`

Answer

b

Explanation

Number of `alpha`-paticles emitted `=(232-208)/(4=6)`
Decreases in charege number due to `alpha`-emission `=12`
But actual decrease in charege number `=90-82=8`.
Clearly, four `beta`-particles are emitted.