An atom has atomic mass 232 atomic number 90. During the course of disintegration, it emits `2 beta`particles and few `alpha` particles. The resultant atom has atomic mass 212 and atomic number 82. How many `alpha` particles are emitted during this process?

Explanation

The decreases in atomic mass
= (233 - 212) = 20
Decrease in mass occurs due to emission of `alpha`particles. Let x be the number of alpha particles emitted.
Mass of 'x' `alpha`particles = 4x
so, 4x = 20
or `x = (20)/(4) = 5`
Alternative method: This can also be determined by the application of the following equation: No of `beta`particles emitted = 2 `xx` No. of `alpha`particles emitted
`-(Z_("parent") - Z_("Final product"))`
`2 = 2 xx x (90 - 82)`
x = 5