Turning copper into gold - The dream of every alchemist
In a room laden with glass jars, tubes and chemicals, air rich with the intoxicating aroma of several chemical substances, a few men relentlessly toiling away in excitement in an effort to obtain something that would gift humans with the power to generate riches: a formula that can convert copper to gold. This is a typical scene from the stories set in medieval times depicting the life of an alchemist.
Alchemy is an ancient tradition that believed in the possibility of converting a lesser metal to gold apart from discovering an elixir that would make man immortal. There are several obscure documents which describe such a process, though there is no scientific evidence to prove itconclusively. Many believe it is possible. Is it really possible to convert copper to gold? What does modern science say?
It would be an interesting tale to narrate the various attempts made by alchemists to achieve such a feat. As far as the modern science is concerned, one could say that all they did was to carry out various kinds of chemical reactions in the hope of arriving at a chemical reaction which can turn a lesser metal to gold. To find out if they could ever reach such a goal, let us try to understand what a chemical reaction is.
Though we find thousands of substances around us, all of them are fundamentally made up of not more than about 118 elements. These elements are listed out in what is known as the periodic table. Everything we find around us is a combination of these elements in various forms and proportions.
When these elements combine with each other they produce interesting and amusing substances. Two elements which are poisonous and hazardous to human life, sodium and chlorine, when combined become an indispensable commodity and an essential ingredient of every recipe: sodium chloride, the common salt! Oxygen and hydrogen when combined become the most important substance without which life on earth would not have been possible: water! Iron, a symbol of strength and support, a material which is part of every building and bridge, when combined with oxygen turns into something everyone despises, rust!
These combinations are possible through processes called chemical reactions. To understand what is meant by a chemical reaction, we need to have a closer look at the structure of the constituent elements. All of these elements are ultimately made of what are called atoms. Atoms are the basic building blocks of matter. Every atom is like a brick, by repeated arrangement of which a building called an element is made. All elements are nothing but three dimensional stacks of these atoms.
An atom has a central nucleus and electrons which revolves around the nucleus in orbits akin to a planet revolving around the sun, though modern theories have shown that this is strictly not the case, this model will suffice for a crude understanding of an atom.
The nucleus has protons and neutrons and as the name suggests neutrons are neutral and protons are positive in charge. The electrons that revolve around the nucleus are negatively charged to keep the atoms neutral as a whole. This means the number of electrons is equal to the number of protons in atoms.
Now, the question is where did the ancient alchemists go wrong? What gives identity to an atom is the number of protons. If you have 7 protons in the nucleus, it is a nitrogen atom and if you have 8, it is oxygen. Note that these two elements differ only by one proton but are totally different in nature. The number of neutrons would also be different but that is not so important (Different number of neutrons will not alter the element, it only creates a close cousin of the element called an isotope).
Chemical reactions merely make atoms loose or gain their electrons or combine different kinds of atoms to form molecules. Starting from the digestion process that happens in our elementary tract to the explosive dynamite - all are chemical reactions. What essentially happens is the modifications and bonding of the atoms; this means they either loose or gain electrons or combine with other kinds of atoms from other elements to form molecules. None of the reactions that are carried out this way can alter the core of the atom, the nucleus. Only if one can change the number of protons in the nucleus can one turn copper to gold.
To be precise, copper has 29 protons and gold has 47 protons, all you need to do is add 18 protons to the nucleus of copper. Well, if one can do that one could turn copper to gold. It is a number gamebut no chemical reaction can achieve such a feat! Alchemists had absolutely no clue about this fact. Would then such a thing be ever possible?
In reality, how does one alter the composition of any nucleus? Well, if one wants to do it, one needs enormous amount of energy to rip apart the nucleus because the nucleus of an atom is very tightly bound. Such a reaction is not chemical in nature; it is called a nuclear reaction. It is not until the beginning of the 20th century, when nuclear reactions were made possible, that such a possibility opened up.
In nuclear reactors and accelerators, one can in principle convert any element to any other element by doing a suitable nuclear reaction. However, the secret that the identity of an element lies in the nucleus of a substance, and to change it one needs to alter its nucleus was something not known to the alchemists. Through any of the reactions, however bizarre and intense or by any amount of heating, boiling, melting, they could never have achieved a nuclear reaction.
One might be curious to know whether such a thing happens naturally. Well, certain elements loose protons and turn into other elements which is called radioactivity. Is there any element which gains protons and turns into a higher element naturally? The answer is no and yes. It does not happen anywhere on earth naturally, as we know. However, it happens every second in stars, the closest being the sun. Enormous amount of hydrogen fuse into helium every second in what is know as a nuclear fusion reaction to produce massive energy. Almost all the stars produce elements everyday through nuclear reactions and thus they are called the foundries that generate the elements.
One can turn any element to another element through a nuclear reaction. One could therefore in this context call nuclear science as 'modern alchemy'. However, the production cost of gold in this method is so high that the very purpose of such a conversion is defeated. One would spend more than the cost of the gold in producing it this way. Nevertheless, for a true alchemist, this is indeed a dream come true.
More About Author
Dr. Satyajit K.T is a Physicist and a Teacher. He is presently working as an Assistant Professor of Physics at Amrita Vishwa Vidyapeetham, Coimbatore, Tamil Nadu. His doctoral work is in the field of atomic physics and he continues to do research in the same area. He also holds interest in Adventure Sports, Psychology, Literature and Music.
A true life enthusiast with varied interests and a creative outlook, he firmly believes that Science is a fascinating subject, which requires simple teaching methodologies; so as to reach the common man. He also believes that the future of the science is in the hands of the youth of India.
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