Chapter 24, Problem 24.22P

(a)

Interpretation Introduction

Interpretation:

Mode of decay has to be predicted for ${}^{15}C$.

Concept Introduction:

Nuclides that are unstable generally decay in a mode that changes its N/Z ratio to the band of stability.

• Nuclides having many neutrons (Neutron-rich nuclides) have a high N/Z ratio and lies above the band of stability. Therefore, to decrease N/Z ratio these nuclides undergo ${\beta }^{-}$ decay.
• Nuclides having many protons (Proton-rich nuclides) have a low N/Z ratio and lies below the band of stability. Therefore, to increase N/Z ratio these nuclides undergo $e^{-}$ capture and/or ${\beta }^{+}$ decay. Heavier elements mostly undergo $e^{-}$ capture whereas lighter elements undergo ${\beta }^{+}$ emission.
• Nuclides having $Z>83$ are considered as too heavy to be stable. To decrease the values of Z and N, it undergoes $\alpha$ decay.

(b)

Interpretation Introduction

Interpretation:

Mode of decay has to be predicted for ${}^{120}Xe$.

Concept Introduction:

Nuclides that are unstable generally decay in a mode that changes its N/Z ratio to the band of stability.

• Nuclides having many neutrons (Neutron-rich nuclides) have a high N/Z ratio and lies above the band of stability. Therefore, to decrease N/Z ratio these nuclides undergo ${\beta }^{-}$ decay.
• Nuclides having many protons (Proton-rich nuclides) have a low N/Z ratio and lies below the band of stability. Therefore, to increase N/Z ratio these nuclides undergo $e^{-}$ capture and/or ${\beta }^{+}$ decay. Heavier elements mostly undergo $e^{-}$ capture whereas lighter elements undergo ${\beta }^{+}$ emission.
• Nuclides having $Z>83$ are considered as too heavy to be stable. To decrease the values of Z and N, it undergoes $\alpha$ decay.

(c)

Interpretation Introduction

Interpretation:

Mode of decay has to be predicted for ${}^{224}Th$.

Concept Introduction:

Nuclides that are unstable generally decay in a mode that changes its N/Z ratio to the band of stability.

• Nuclides having many neutrons (Neutron-rich nuclides) have a high N/Z ratio and lies above the band of stability. Therefore, to decrease N/Z ratio these nuclides undergo ${\beta }^{-}$ decay.
• Nuclides having many protons (Proton-rich nuclides) have a low N/Z ratio and lies below the band of stability. Therefore, to increase N/Z ratio these nuclides undergo $e^{-}$ capture and/or ${\beta }^{+}$ decay. Heavier elements mostly undergo $e^{-}$ capture whereas lighter elements undergo ${\beta }^{+}$ emission.
• Nuclides having $Z>83$ are considered as too heavy to be stable. To decrease the values of Z and N, it undergoes $\alpha$ decay.