Hopefully you already know about protons, neutrons and electrons? Atoms are made from those three things: protons & neutrons clump together into a positively charged ‘nucleus’ and negatively charged electrons are attracted to the nucleus so they orbit around it. Electrons can’t get sucked into the nucleus, though, because something called ‘quantum mechanics’ says they must stay on nice circular orbits and not fall down to the middle.
Does that make sense? Please feel free to ask more if you want… in exchange for a vote of course 😉