The nucleus of an atom contains positively charged particles, called protons, and neutral particles, called neutrons. how is the nucleus of an atom held together?

The fundamental force holding the nucleus together is the "strong force."
At extremely short range, it is stronger than electrostatic repulsion, and allows protons to stick together in a nucleus even though their charges repel each other.

Hey how did you manage to type such a big lab report

What is the gold assay