Nucleons in nuclei are bound by the strong force. It's (vaguely) analogous to the way the electromagnetic force still binds neutral molecules together (van der

Nucleons in nuclei are bound by the strong force. It's (vaguely) analogous to the way the electromagnetic force still binds neutral molecules together (van der Waals force). At the scale of the nucleus, gravity is many, MANY orders of magnitude weaker.