Question

Alchemists in the Middle Ages dreamed of converting base metals, such as lead, into precious metals—gold and silver. Why could they never succeed? Today could we convert lead to gold?

Answer 1

Each element has a different but fixed number of protons in the nucleus of the atom, which is the atomic number, the transmutation of one chemical element into another involves changing that number. Such a nuclear reaction requires millions of times more energy than was available through chemical reactions. Thus, the alchemist's dream of transmuting lead into gold was never chemically achievable.

It is indeed possible—all you need is a particle accelerator, a vast supply of energy and an extremely low expectation of how much gold you will end up with. More than 30 years ago nuclear scientists at the Lawrence Berkeley National Laboratory (LBNL) in California succeeded in producing very small amounts of gold from bismuth, a metallic element adjacent to lead on the periodic table. The same process would work for lead, but isolating the gold at the end of the reaction would prove much more difficult, says David J. Morrissey, now of Michigan State University, one of the scientists who conducted the research. “We could have used lead in the experiments, but we used bismuth because it has only one stable isotope,” Morrissey says. The element’s homogeneous nature means it is easier to separate gold from bismuth than it is to separate gold from lead, which has four stable isotopic identities.

http://www.scientificamerican.com/article/fact-or-fiction-lead-can-be-turned-into-gold/
Read more: http://www.chemistryexplained.com/Te-Va/Transmutation.html#ixzz461bNuuja