Chapter 25.1, Problem 4LC

Interpretation Introduction

Interpretation: To compare the change in an atomic number of a nucleus by three different radiations.

Concept Introduction: The process which involves the formation of more than one nuclide via a collision between two nuclei or between one nucleus and a subatomic particle, is known as a nuclear reaction.

Answer to Problem 4LC

In alpha decay, the atomic number is decreased by two units, in beta decay, it is decreased by one unit while there is no change in atomic number during gamma decay.

Explanation of Solution

The three types of radioactive decay are as follows:

1. Alpha decay
2. Beta decay
3. Gamma decay

Alpha decay: The radiation that emits an alpha particle (Helium nuclei) is known as alpha radiation. An alpha particle comprises two protons and two neutrons and also consists of a double positive layer.

The chemical equation depicting alpha radiation is as follows:

  $\text{U}\stackrel{\text{radioactive decay}}{\to }\text{T}\text{h}+\text{H}\text{e}$

In alpha decay, the atomic number of the product decreases by two.

Beta decay: When an electron is formed that results from breaking a neutron, this electron is termed a beta particle. The neutron breaks into a proton and an electron is released in the beta radiation.

The chemical equation depicting beta radiation is as follows:

  $\text{C}\to \text{N}+\text{e}$

In beta decay, the atomic number of the product decreases by one.

Gamma decay: Gamma ray is a high-energy photon that is emitted by a radioisotope. During radioactive decay, neutrons emit gamma rays along with the formation of alpha and beta particles.

The chemical reaction depicting gamma radiation is as follows:

  $\text{T}\text{h}\to \text{R}\text{a}+\text{H}\text{e}+\gamma$

There is no change in mass or atomic number during gamma decay.

Conclusion

In alpha decay, the atomic number is decreased by two units, in beta decay, it is decreased by one unit while there is no change in atomic number during gamma decay.