What subatomic particles are found in the nucleus of an atom?

The correct choice is that protons and neutrons are the subatomic particles found in the nucleus of an atom. The nucleus serves as the central core of the atom and is made up of these two types of particles.

Protons are positively charged particles, and their number within the nucleus determines the atomic number of an element, essentially defining what element it is. Neutrons, on the other hand, are neutral particles that do not have an electric charge. They play a crucial role in adding mass to the atom and can influence the stability of the nucleus alongside protons.

The combination of protons and neutrons constitutes the atomic mass, as electrons, which carry a negative charge, are located in orbitals outside the nucleus and do not contribute to the mass of the atom significantly. This distinction is fundamental to understanding atomic structure and how elements interact in chemical reactions. In summary, the presence of both protons and neutrons in the nucleus is crucial for the identity and stability of an atom.