Atomic nuclei are the central part of an atom, consisting of protons and neutrons. Protons carry a positive charge, while neutrons are neutral. The number of protons in the nucleus determines the element, such as hydrogen or carbon. Together, protons and neutrons are called nucleons. The strong nuclear force binds these nucleons together, overcoming the repulsion between the positively charged protons. The size of the nucleus is very small compared to the entire atom, which includes the surrounding electrons. Understanding atomic nuclei is essential for fields like nuclear physics and chemistry.