Elementary particles, such as quarks and leptons, are fundamental components of matter and play a crucial role in the structure of atoms. Protons and neutrons, which make up the atomic nucleus, are themselves composed of quarks, highlighting that elementary particles do reside within the nucleus. The discussion raises questions about whether elementary particles exist solely in the nucleus or if they can be found elsewhere, indicating some ambiguity in the original inquiry. Participants emphasize the importance of attempting to answer questions independently before seeking assistance. Overall, the conversation underscores the foundational role of elementary particles in atomic structure.