Choose an element for your project, and determine the number of protons and neutrons within the nucleus. For example, nitrogen has seven protons and seven neutrons.
Count out a number of polystyrene foam balls equal to the number of protons within your nucleus. For example, you need seven balls for the protons in nitrogen.
Paint the protons any color you choose. Set them aside to dry.
Paint the remaining balls, representing the neutrons, in a different color. Set them aside to dry.
Glue the balls together to create an abstract shape, alternating protons and neutrons.