Radiation Safety Practice Exam

What constitutes the nucleus of an atom?

1. Electrons and neutrons

2. Protons and neutrons

3. Protons and electrons

4. Neutrons and photons

The correct answer is: Protons and neutrons

The nucleus of an atom is made up of protons and neutrons, which are collectively known as nucleons. Protons are positively charged particles that determine the element's identity and its position on the periodic table, while neutrons are neutral particles that contribute to the atomic mass and stability of the nucleus. Electrons, although critical for the structure and behavior of an atom, are not part of the nucleus; instead, they orbit around the nucleus in defined energy levels or shells. Photons, on the other hand, are particles of light and do not have mass or charge, which means they do not contribute to the nucleus either. Understanding the composition of the nucleus is fundamental in various areas such as nuclear physics, chemistry, and radiation safety, as the stability and behavior of the nucleus play a key role in radioactive decay and other nuclear processes.