Before chemistry was a science, there was alchemy. One of the supreme quests of alchemists was to transmute (transform) lead into gold.

Lead (atomic number 82) and gold (atomic number 79) are defined as elements by the number of protons they possess. Changing the element requires changing the atomic (proton) number. The number of protons in an element cannot be altered by any chemical means. However, physics may be used to add or remove protons and thereby change one element into another. Because lead is stable, forcing it to release three protons requires a vast input of energy, so much so that the cost of transmuting it greatly surpasses the value of any resulting gold.

History

Transmutation of lead into gold isn't just theoretically possible—it's been achieved! It's been reported that Glenn Seaborg, 1951 Nobel Laureate in Chemistry, succeeded in transmuting a minute quantity of lead (although he may have started with bismuth, another stable metal often substituted for lead) into gold in 1980. An earlier report (1972) details an accidental discovery by Soviet physicists at a nuclear research facility near Lake Baikal in Siberia of a reaction that had turned the lead shielding of an experimental reactor into gold.

Transmutation Today

Today, particle accelerators routinely transmute elements. A charged particle is accelerated using electrical and magnetic fields. In a linear accelerator, the charged particles drift through a series of charged tubes separated by gaps. Every time the particle emerges between gaps, it's accelerated by the potential difference between adjacent segments.

In a circular accelerator, magnetic fields accelerate particles moving in circular paths. In either case, the accelerated particle impacts a target material, potentially knocking free protons or neutrons and making a new element or isotope. Nuclear reactors also may be used for creating elements, although the conditions are less controlled.

In nature, new elements are created by adding protons and neutrons to hydrogen atoms within the nucleus of a star, producing increasingly heavier elements, up to iron (atomic number 26). This process is called nucleosynthesis. Elements heavier than iron are formed in the stellar explosion of a supernova. In a supernova, gold may be transformed into lead—but not the other way around.