Chapter 24, Problem 88A

Interpretation Introduction

Interpretation:

For each segment of graph, type of decay and changes in atomic and mass number is to be determined.

Concept introduction:

In a nuclear reaction, unstable nuclide disintegrates into stable nuclide with emission of various radiations spontaneously. It is called radioactivity of nucleus. Emission of rays like alpha, beta and gamma rays occur in the process which changes the identity of nucleus.

During a nuclear change, an element undergoes change in its atomic mass or atomic number or both by emission of charged particles such as beta particle, alpha particle. Beta particle is one that has unit negative charge and alpha particle is one that has 2 unit positive charges and is equivalent to helium atom ${}_2^4\text{He}$. Emission of proton, beta particle, alpha particle causes a change in atomic number of element.

Answer to Problem 88A

Segment A indicates Alpha decay in which element with Z equal to 90 changes to 88 and A changes from 232 to 228.

Segment B indicates beta decay in which element with Z equal to 88 changes to 89 and A remains unchanged.

Segment C indicates beta decay in which element with Z equal to 89 changes to 90 and A remains unchanged.

Segment D indicates Alpha decay in which element with Z equal to 90 changes to 88 and A changes from 228 to 224.

Explanation of Solution

Segment A of the graph indicates Alpha decay as it consists of change in atomic number (Z) by 2 and mass number (A) by 4. This means ${}_{\text{2}}^{\text{4}}\text{He}$ particle is emitted which composes alpha radiation. While undergoing alpha decay, element with Z equal to 90 changes to 88 and A changes from 232 to 228.

Segment B of the graph indicates beta decay as it consists of only change in atomic number (Z) by 1. This means ${\text{e}}^{-}\text{or}\text{β}$ is emitted which composes beta radiation. While undergoing beta decay, element with Z equal to 88 changes to 89 and A remains unchanged.

Segment C of the graph indicates beta decay again as it consists of only change in atomic number (Z) by 1. This means ${\text{e}}^{-}\text{or}\text{β}$ is emitted which composes beta radiation. While undergoing beta decay, element with Z equal to 89 changes to 90 and A remains unchanged.

Segment D of the graph indicates Alpha decay as it consists of change in atomic number (Z) by 2 and mass number (A) by 4. This means ${}_{\text{2}}^{\text{4}}\text{He}$ particle is emitted which composes alpha radiation. While undergoing alpha decay, element with Z equal to 90 changes to 88 and A changes from 228 to 224.

Conclusion

Segment A indicates Alpha decay in which element with Z equal to 90 changes to 88 and A changes from 232 to 228.

Segment B indicates beta decay in which element with Z equal to 88 changes to 89 and A remains unchanged.

Segment C indicates beta decay in which element with Z equal to 89 changes to 90 and A remains unchanged.

Segment D indicates Alpha decay in which element with Z equal to 90 changes to 88 and A changes from 228 to 224.