A nucleus `._n^ m X` emits one `alpha-`particle and two `beta-`particles. The resulting nucleus is

Options

A. `"" _(n-4) ^(m-6) Z`
B. `"" _(n) ^(m-6) Z`
C. `"" _(n) ^(m-4) X`
D. `"" _(n-2) ^(m-4) Y`

Answer

C

Explanation

When an alpha particle `("" _(2) ^(4) He)` is emitted, the mass number and the atomci number of the daughter nucleus decrease by four and two repspectively When a beta particle `(beta ^(-1))` is emitted, the atomic number remains the same.
`therefore"" _(n) ^(m) X overset (alpha)to "" _(n-2) ^(m-4) Y overset(2 beta ^(-))to "" _(n) ^(m-4) X`