Chapter U1.15, Problem 12E

Interpretation Introduction

Interpretation:

The final product must be identified when ₁₁₉Pt¹⁹⁷ undergoes beta decay and the daughter isotope so formed also undergoes beta decay.

Concept introduction:

A beta particle can be represented as _-1e⁰.

Atomic number and mass number of a beta particle is thus -1 and 0 respectively.

There is no change of mass number of daughter isotope when beta decay takes place. But atomic number increases by one unit.

Answer to Problem 12E

The final product will be ₁₂₁Tl¹⁹⁷.

Explanation of Solution

The beta decay of the given nuclear reaction can be represented as follows.

₁₁₉Pt¹⁹⁷=₁₂₀X¹⁹⁷ + _-1e⁰

₁₂₀X¹⁹⁷=₁₂₁Tl¹⁹⁷ + _-1e⁰

After each beta decay there is one unit increase in atomic number but mass number remains the same. As the starting nuclide has atomic number 119 so after two consecutive beta decay the atomic number of final product will be 121. Mass number will be same as starting nuclide which is 197.

Conclusion

Thus, the final product will be ₁₂₁Tl¹⁹⁷.