2025 TEAS 7 Science Complete Practice Test by ATI

An atom is fundamentally composed of three types of subatomic particles: protons, neutrons, and electrons. Protons are positively charged particles found in the nucleus of the atom, and their number determines the atomic number and identity of the element. Neutrons are neutral particles, also located in the nucleus, that provide stability to the atom. Electrons are negatively charged particles that orbit the nucleus in various energy levels.

The combination of these particles defines the mass and charge of the atom, and they play crucial roles in chemical bonding and reactions. Protons and neutrons together make up the nucleus, while electrons exist in energy levels surrounding the nucleus, influencing the atom's reactivity and properties. This fundamental understanding is critical in recognizing how atoms interact to form molecules and how they participate in chemical processes.

Other choices presented do not accurately represent the particles that make up an atom, as they include combinations of particles that either do not exist in atoms or represent different aspects of atomic structure or behavior.