Atoms are the fundamental building blocks of all matter in the universe. From the air you breathe to the device you are holding, everything is composed of these incredibly small particles. An atom consists of two main regions: a dense central core and a vast surrounding space. The Nucleus: Located at the center, it contains protons (positive charge) and neutrons (no charge). It holds more than 99.9% of the atom's mass. The Electron Cloud: A much larger region around the nucleus where electrons (