The basic components of an atom are protons, neutrons, and electrons. Protons and neutrons reside in the nucleus at the atom's center and contribute to its mass. Protons carry a positive charge, while neutrons are neutral. Electrons, which are negatively charged, orbit the nucleus in specific energy levels. The arrangement and number of these subatomic particles determine the element's chemical properties and behavior in reactions, making them fundamental to the study of chemistry and physics.