Chapter 24, Problem 24.5P

Interpretation Introduction

Interpretation:

Reason for why ${}_2^{3}He$ is stable whereas ${}_2^{2}He$ cannot be detected has to be explained.

Concept Introduction:

Nuclear stability means that the nucleus is stable meaning that it does not spontaneously emit any kind of radioactivity.

Nuclear stability can be explained based on neutron proton ratio (N/Z) in the nucleus.

For a stable atoms having low atomic number, N/Z ratio is close to 1. When atomic number increases N/Z becomes greater than 1.

General rules for predicting the nuclear stability is given below,

• If the nucleus contains 2, 8,20,50,82 or 126 protons or neutrons, then they are generally considered as stable than the nuclei that do not possess these numbers.
• If the nuclei has even number of both protons and neutrons, then they are considered as stable as those with odd number of these particles.
• All isotopes of elements with atomic number higher than 83 are radioactive.