An Atom is the most basic chemical unit in the world! It is powered by electrons (negative charge), Protons (positive charge) and Neutrons(neutral/no charge). Atoms form substances like Nickel, Carbon, Hydrogen, etc. In other words, all the substances in the periodic table (picture in the answer). Substances can take protons and electrons from other substances to make it a new substance. I will also include a sketch I drew of an Atom and the internet's atom. the Neutron in the Atom moves around the Atom faster than the speed of light. The earliest atoms were primarily hydrogen and helium, which are still the most abundant elements in the universe. It took 380,000 years for the universe to cool down enough to slow down the electrons so that the nuclei could capture them to form the first atoms. All the parts of an Atom circle around the Nuclei or Nucleus.
If you need more help I would be glad to help!:)
~"AB84"~