Question

A nucleus of an element X which has the symbol `""_84^202` X emits an alpha particle and then a beta particle. The final nucleus is `""_"b"^"a"` Y Find a and b.

Answer 1

Initia I ly element is rep resented by ₈₄X²⁰²
a particle is rep resented by ₂He⁴ this means it contains 2 protons and 2 neutrons so mass of a particle is 4 unit. Thus after emitting a particle mass number of element would decrease by 4 unit and atomic number of element would decrease by 2.

So after emitting a particle ₈₄X²⁰² would become _84-2X^202-4= ₈₂X198.

13 particle is represented by _-1e° after emitting a β particle atomic number of element would increase by 1 unit and mass number of element would remain unchanged.

So after emitting a ~ particle ₈₂X198 would become ₈₂X198 = ₈₃X198.

The daughter nucleus is rep resented by _bY^a

^_bYa = ₈₃X^198.

a= 198

b= 83.