How many alpha and beta particles are emitted when uranium `._(92)^(238)U` decays to lead `._(82)^(206)Pb` ?

Options

A. `6 alpha` and `6 beta`
B. `6 alpha` and `8 beta`
C. `8 beta` and `8 alpha`
D. `6 beta` and `8 alpha`

Answer

D

Explanation

Suppose no. of `alpha` particles emitted =x and the no. of `beta` particles emitted =y Then,
`""_(92)U^(238) to ""_(82)Pb^(206) x""_(2)He^(4) + y ""+_(-1)e^(0)`
Equating the mass number on both sides ,we get `238 = 206 + 4x+0Y` or `4x=238-206=32` or `x=8`
Equating the atomic number on both side we get `92 =82 + 2x-y=82 +2 xx8-y`
`y=82 + 16` or `y=6`