Chapter U1.15, Problem 2E

Interpretation Introduction

Interpretation:

Difference between alpha decay and beta decay must be explained.

Concept introduction:

In alpha decay, one of the daughter nuclides is an alpha particle whereas, in beta decay, one of the daughter elements is a beta particle.

Answer to Problem 2E

In alpha decay, the daughter element has mass number 4 units less as compared to the original element. There are two units decrease in the atomic number.

In beta decay, there is no change in the mass number of the daughter element but the atomic number is increased by one unit of the daughter element.

Explanation of Solution

As an alpha particle is nothing but a helium atom, so it has mass number 4 and atomic number 2. Thus, after alpha decay, there is a decrease in mass number by 4 units and a decrease in atomic number by 2 units. A beta particle has no mass number and -1 charge. This is basically an electron. So, to have the mass balance in both the side of a nuclear reaction, there is no change in the mass number of the daughter nuclide but there is one unit increase in the atomic number of the daughter nuclide.