A copper atom has a nucleus with 29 protons and 35 neutrons. A total of 29 electrons circle the nucleus in four orbits. To make your 3D model of a copper atom, you should have a picture of one to help you arrange the model. You can use polystyrene balls and pipe cleaners or another bendable, stiff metal rods, to hold the electrons in place around the nucleus. You can use a wide polystyrene disc to mount your copper atom on.
Create the inner ring. The inner ring around the large ball has two electrons. With the pipe cleaners, make a circle that will fit around the large nucleus with two smaller balls on opposite sides. Connect each of the smaller balls to the large ball with pipe cleaners.
Create the second ring. It has eight electrons. Using the pipe cleaners, attach the eight small balls evenly around in a circle that is bigger than the first ring and fits nicely next to it. Line up two of the balls on this second ring with the two balls from the first ring. Use a short pipe cleaner to attach these balls together.
Create the third ring. It has 18 electrons. Arrange a third circle of evenly spaced small balls to fit around the second ring. Line up the third ring's balls with the second ring and first ring balls and attach with short pipe cleaners.
Create the fourth ring. This only has one electron on it. You will have to twist some pipe cleaners together and shape a circle with one ball on it large enough to circle around the third ring. Connect the one ball to the string of balls on the other rings with a pipe cleaner. To keep the edges of the fourth ring up, connect short pipe cleaners along the fourth ring and insert them into balls on the third ring.
Attach your model to the base. Push the metal rod into the nucleus ball and insert it into the polystyrene disc. You can paint the copper atom model if you like.