The number of `alpha`-and `beta`-particles emitted in the nuclear reaction, `._(90)Th^(228) to ._(83)Bi^(212)`, respectively are

Options

A. `4 alpha` and `1 beta`
B. `3 alpha` and `7 beta`
C. `8 alpha` and `1 beta`
D. `4 alpha` and `7 beta`

Answer

a

Explanation

Number of `alpha`-particles
`= ("mass number of emitter" - "mass number of end product")/(4)`
`(228 - 212)/(4) = (16)/(4) = 4`
Number of `beta`-particles `= 2xxalpha-"particle" - ("difference in atomic number")`
`= 2xx4 - (90 - 83) = 8 -7 =1`
Hence, `alpha` and `beta`-particles, emitted are 4 and 1 respectively.