Back to Teachers Home

NOVA scienceNOW: Island of Stability

Program Overview

Scientists describe how forces in the atomic nucleus work to keep the atom stable. They then explain how researchers make new elements and discuss why large, man-made elements—those beyond atomic number 102 on the periodic table—are generally unstable. However, certain atoms with atomic numbers above 102 are stable because their protons and neutrons arrange themselves in a particularly efficient way. For example, scientists predict that an atom with 114 protons and 184 neutrons would be one such element. Because this atom is expected to be stable even when those near it on the periodic table are unstable, it is referred to as an "Island of Stability." If this prediction proves correct, scientists will gain important insights into the stability of the atomic nucleus.

This NOVA scienceNOW segment:

• recalls that elements above atomic number 92 are man-made rather than naturally occurring.

• reviews the concept that protons are positively charged and repel each other, while neutrons have no charge and help buffer the protons' repelling forces.

• introduces the idea that, inside an atom's nucleus, the protons and neutrons may be organized in rings, with each ring holding a specific number of protons and neutrons.

• states that Island of Stability is a nickname for atoms exhibiting exceptional atomic stability.

• reports that an element with 114 protons has been made by fusing plutonium (atomic number 94) and calcium (atomic number 20), but that this form did not have 184 neutrons, the number that would be needed for the element to be as stable as possible.

Taping Rights: Can be used up to one year after the program is taped off the air.