Chapter 39, Problem 14A

(a)

To determine

The effect of the ejection of one alpha particle on the atomic number of an atom.

Explanation of Solution

Introduction:

The radioactive decay is the process in which the composition of the nucleus varies due to ejection of radioactive particles.

The atomic number of an atom is same as the number of protons in the nucleus of that atom.

The number of the protons in the nucleus of an atom reduces by two unit and mass number increases by four units due to ejection of one alpha particle.

The atomic number of an atom reduces by two units due to ejection of one alpha particle in radioactive decay.

Conclusion:

Thus, the atomic number of an atom reduces by two units due to ejection of one alpha particle in radioactive decay.

(b)

To determine

The effect of the ejection of one alpha particle on the atomic mass of an atom.

Explanation of Solution

Introduction:

The radioactive decay is the process in which the composition of the nucleus varies due to ejection of radioactive particles.

The atomic mass of the atom reduces by four units due to ejection of one alpha particle in radioactive decay.

Conclusion:

Thus, the atomic mass of the atom reduces by four units.