Question

Plz help me thanks ^-^

Answer 1

Answer: The isotopic symbol of unknown particle is $_{2}^{4}\textrm{He}$

Explanation:

In a nuclear reaction, the total mass and total atomic number remains the same.

For the given fission reaction:

$^{228}_{90}\textrm{Th}\rightarrow ^A_Z\textrm{X}+^{224}_{88}\textrm{Ra}$

To calculate A:

Total mass on reactant side = total mass on product side

228 = A + 224

A = 4

To calculate Z:

Total atomic number on reactant side = total atomic number on product side

90 = Z + 88

Z = 2

Hence, the isotopic symbol of unknown particle is $_{2}^{4}\textrm{He}$