Chapter 20, Problem 20.7QP

Interpretation Introduction

Interpretation: The type of emission should be explained when a nucleus exhibit the above or below the stability belt.

Concept introduction:

Alpha ( $\alpha$) particle: It consist of two protons and two neutrons bound together into a particle identical to a helium ( ${}^4{\text{He}}_2$) nucleus.

Alpha decay: it is a type of radioactive decay in which an atomic nucleus emits an alpha ( $\alpha$) particle

${\text{β}}^{+}$Decay (positron) emission:

Unstable atomic nuclei with an excess of proton may undergo ${\text{β}}^{+}$ decay.

It’s popularly called as positron ( ${\text{β}}^{+}$) emission.

$\text{p }\to {\text{n + e}}^{\text{+}}{\text{ + ν}}_{\text{e}}$

Here proton is converted into a neutron, a positron, and an electron neutrino.

Neutron is a subatomic particle, and it’s denoted as ${\text{n}}^1{}_0$.

Neutron contains no net electric charge and mass slightly larger than proton.

Proton and neutrons constitute the nuclei.

Nuclear Belt of Stability:

Most elements have isotopes and by plotting we can identify whether isotope is stable or not

 The plot shows only the stable isotopes, this graph is often called the Nuclear Belt of Stability. The plot indicates that lighter nuclides (isotopes) are most stable when the neutron/proton ratio is 1/1.