A radiaoactive nucleus (initial mass number `A` and atomic number `Z` emits `3 alpha`- particles and 2 positrons The ratio of number of neutrons to that of proton in the final nucleus will be

Options

A. `(A -Z -4)/(Z - 2)`
B. `(A- Z - 8)/(Z - 4)`
C. `(A - Z - 4)/(Z - 8)`
D. `(A - Z - 12)/(Z - 4)`

Answer

C

Explanation

`._(Z)X^(A)overset(3alpha)rarr._(Z-6)Y^(A-12)rarr._(Z-8)Z^(A-12)+2_(1)e^(0)`
`("number of netrons")/("number of protons") = ((A-12)-(Z-8))/(Z-8) = (A-Z-4)/(Z-8)`