What surrounds the central nucleus of an atom?

The central nucleus of an atom is surrounded by electrons. Electrons are negatively charged particles that occupy the space around the nucleus, forming what is often referred to as an electron cloud. This cloud represents the regions where electrons are most likely to be found as they move in specific energy levels or shells around the nucleus.

In contrast, protons and neutrons make up the nucleus itself, with protons having a positive charge and neutrons being neutrally charged. Quarks are the fundamental particles that compose protons and neutrons, but they are not found outside the nucleus; instead, they are confined within these nucleons. Therefore, the presence of electrons in the outer region is what primarily defines the atom's structure and its interactions with other atoms.