Answer: a. [tex]_{1}^{1}\textrm{H}[/tex]
b. Atomic number of the nucleus formed is 89 which is actinium.
Explanation:
Nuclear fission reactions are defined as the reactions in which a heavier nuclei breaks down in two or more smaller nuclei.
In a nuclear reaction, the total mass and total atomic number remains the same.
For the given fission reaction:
[tex]^{232}_{90}\textrm{Th}+^A_Z\textrm{X}\rightarrow ^{227}_{89}\textrm{Ac}+^{4}_{2}\textrm{He}+2^1_0\textrm{n}[/tex]
To calculate A, mass number
Total mass on reactant side = total mass on product side
232 + A = 227+4+2
A = 1
To calculate Z, atomic number
Total atomic number on reactant side = total atomic number on product side
90 + Z = 89 +2+ 0
Z = 1
[tex]^{232}_{90}\textrm{Th}+^1_1\textrm{X}\rightarrow ^{227}_{89}\textrm{Ac}+^{4}_{2}\textrm{He}+2^1_0\textrm{n}[/tex]
The isotopic symbol of element with atomin number of 1 and mass number of 1 is [tex]_{1}^{1}\textrm{H}[/tex]
The atomic number of the nucleus formed is 89 which is actinium.
