During alpha decay of a nucleus, how does the neutron to proton ratio change?

Options

A. Increases
B. Decreases
C. Remains constant
D. May increase or decrease

Answer

A

Explanation

Cosider the nuclear reaction for `alpha` decay
`""_92U^238 to ""_90Th^234 +""_2He^4`
before the `alpha` decay
No. of protons = 92, No. of neutrons = 238 - 92 = 146
`therefore (n_N)/(n_P) = 146/92`
After the `alpha` decay ` n_P = 90 , n_N =234 - 90 = 144`
`therefore (n_N)/(n_P) = 144/90 " as " 144/90 gt 146/92`
`therefore` the neutrons to protons ratio increases in an `alpha` decay