What is the center of an atom referred to as?

The center of an atom is referred to as the nucleus. This is the dense region that contains protons and neutrons, which are the subatomic particles responsible for most of the atom's mass. The nucleus plays a critical role in the stability of the atom and governs its identity as an element through the number of protons it contains. This central part of the atom is surrounded by electron shells, where electrons are located and move around the nucleus. Understanding the structure of the atom is fundamental in the study of chemistry and physics, as the interactions of these particles govern all chemical reactions and atomic behavior.