Answer: a) Tl (Thallium)
b)
![^(210)_(84)\textrm{Bi}\rightarrow ^(206)_(82)\textrm{Pb}+^4_2\textrm{He}](https://img.qammunity.org/2020/formulas/chemistry/middle-school/49f3ju3s0noaiii9h6gy3kz7xga8uqw23i.png)
![^(218)_(84)\textrm{Bi}\rightarrow ^(214)_(82)\textrm{Pb}+^4_2\textrm{He}](https://img.qammunity.org/2020/formulas/chemistry/middle-school/ur98nezuiq0ke66pvzsj0eyypolr20fvi6.png)
![^(214)_(84)\textrm{Bi}\rightarrow ^(210)_(82)\textrm{X}+^4_2\textrm{He}](https://img.qammunity.org/2020/formulas/chemistry/middle-school/qziazqi8qgc2c5ijzugy87tn475rjnbvih.png)
Step-by-step explanation:
Alpha decay : When a larger nuclei decays into smaller nuclei by releasing alpha particle. In this process, the mass number and atomic number is reduced by 4 and 2 units respectively.
General representation of an element is given as:
![_Z^A\textrm{X}](https://img.qammunity.org/2020/formulas/chemistry/middle-school/arn0rvj6bc7a5zdx8f9o5uczr77fkuw61t.png)
where,
Z represents Atomic number
A represents Mass number
X represents the symbol of an element
Total mass on reactant side = total mass on product side
214= A + 4 , A = 210
To calculate Z:
Total atomic number on reactant side = total atomic number on product side
83= Z + 2, Z = 81
![^(214)_(83)\textrm{Bi}\rightarrow ^(A)_(Z)\textrm{X}+^4_2\textrm{He}](https://img.qammunity.org/2020/formulas/chemistry/middle-school/lf65u3ws0d6vxbntd8734c2b9qa7rbnxey.png)
b)
1.
![^(210)_(84)\textrm{Bi}\rightarrow ^(206)_(82)\textrm{Pb}+^4_2\textrm{He}](https://img.qammunity.org/2020/formulas/chemistry/middle-school/49f3ju3s0noaiii9h6gy3kz7xga8uqw23i.png)
Total mass on reactant side = total mass on product side
210= A + 4 , A = 206
To calculate Z:
Total atomic number on reactant side = total atomic number on product side
84= Z + 2, Z = 82
2.
![^(218)_(84)\textrm{Bi}\rightarrow ^(214)_(82)\textrm{Pb}+^4_2\textrm{He}](https://img.qammunity.org/2020/formulas/chemistry/middle-school/ur98nezuiq0ke66pvzsj0eyypolr20fvi6.png)
Total mass on reactant side = total mass on product side
218= A + 4 , A = 214
To calculate Z:
Total atomic number on reactant side = total atomic number on product side
84= Z + 2, Z = 82
3.
![^(214)_(84)\textrm{Bi}\rightarrow ^(210)_(82)\textrm{X}+^4_2\textrm{He}](https://img.qammunity.org/2020/formulas/chemistry/middle-school/qziazqi8qgc2c5ijzugy87tn475rjnbvih.png)
Total mass on reactant side = total mass on product side
214= A + 4 , A = 210
To calculate Z:
Total atomic number on reactant side = total atomic number on product side
84= Z + 2, Z = 82