The force that holds atoms together is primarily the electromagnetic force. Atoms are made up of protons, neutrons, and electrons. Protons carry a positive charge, while electrons carry a negative charge. The electromagnetic force causes the negatively charged electrons to be attracted to the positively charged protons in the nucleus of the atom.
Additionally, the strong nuclear force plays a crucial role in holding the protons and neutrons together within the nucleus itself. This force is incredibly strong but acts over a very short range, effectively overcoming the repulsive electromagnetic force between the positively charged protons, thereby stabilizing the nucleus.
In summary, while the electromagnetic force is responsible for the attraction between electrons and protons, the strong nuclear force is essential for keeping the nucleus intact. Both forces work together to keep the atom stable and allow for the formation of matter as we know it.