Transmutation Definition
It is derived from the Latin word ‘transmutare’ which means "to change from one form into another". In general, transmutation is any transformation from one form or species into another. (transmute meaning is to change from one form or substance into another). In Chemistry, Transmutation is a process in which the nucleus changes in the number of protons to produce an atom with a different atomic number. It can be done artificially or can occur naturally.
Radioactive decay, nuclear fission, and nuclear fusion can be termed as natural processes by which one element is transformed into another. The first artificial transmutation was done by Lord Rutherford in the year 1911. He bombarded alpha particles on Nitrogen-14 to produce Oxygen-17 with protons.
147N + 42He → 178O + 11H
Here, the total number of protons is 9 and the total mass is 18 on both sides.
Fission and Fusion Reactions
There are two types of nuclear reactions called nuclear fission and nuclear fusion. In the case of nuclear fission, an atom disintegrates into two or lighter atoms on the other hand nuclear fusion occurs when two or more atoms combine or fuse together to form a large or heavy atom.
Nuclear Fission:
The word fission means splitting. Nuclear fission takes place when an unstable isotope (atoms with the same number of protons but a different number of neutrons) is bombarded by high-speed particles, usually neutrons. This splits the nucleus and breaks it down into two smaller isotopes (the fission products) along with three high-speed neutrons, with a release of a large amount of energy. They are used in nuclear power reactors to produce large amounts of energy.
Eg: when a uranium-235 atom is bombarded with a neutron, the heavy nucleus of the uranium splits and produces krypton-94 and barium-139 with the emission of three neutrons and a large amount of energy.
Nuclear Fusion:
The word fusion means " merging of separate elements into a whole". Nuclear fusion means the "union of atomic nuclei to form heavier nuclei resulting in the release of enormous amounts of energy". The energy released in this process is greater than the nuclear fission reaction.
Eg: The fusion process occurs in the sun where the atoms of Hydrogen (isotopes: Hydrogen-3, and Hydrogen-2) Deuterium and Tritium combine in a huge pressure atmosphere with extremely high temperatures to form a neutron and an isotope of Helium.
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Transmutation Reactions
Transmutation of species or elements results in the formation of new elements from radioactive elements with the emission of radiation like alpha, beta or gamma rays. Natural transmutations are spontaneous in-process and usually occur with unstable radioactive elements. The series of chain reactions result in the formation of stable elements. On the other hand, artificial transmutation occurs in nuclear reactors with the bombardment of particles like neutrons.
²²⁸₈₈ Ra → ⁴₂ He + ²¹⁸₈₆ Rn
¹³¹₅₃ I → ¹³¹₅₄ Xe + ⁰₋₁ e
²²₁₁ Na → ²²₁₀ Ne + ⁰₋₁ e
The equations can be balanced by using simple rules. The mass number of reactants and product sides must be conserved in a nuclear change. If there is more than one reactant or product, the sum of the mass numbers must remain the same before and after the reaction. Similarly, the electric charge must be conserved in any transmutation process. Transmutation Alchemy is the conversion of base elements into precious metals (gold or silver).
Did you know?
The first observation of transmutation was done in 1901 when Frederick Soddy and Ernest Rutherford observed thorium changing into radium via radioactive decay. According to Soddy, he exclaimed, "Rutherford, this is transmutation!" To which Rutherford replied, "For Christ's sake, Soddy, don't call it transmutation. They'll have our heads off as alchemists!"
FAQs on Transmutation
1. What exactly is transmutation in the context of Chemistry?
In Chemistry, transmutation refers to the conversion of one chemical element into another. This process involves a change in the atom's nucleus, specifically altering the number of protons. This is fundamentally different from a regular chemical reaction, where only the arrangement of electrons is changed, and the elements involved remain the same.
2. What are the main types of nuclear transmutation?
Nuclear transmutation can be broadly classified into two main types based on how they occur:
- Natural Transmutation: This happens spontaneously in nature without human intervention. It is the process by which unstable radioactive elements undergo radioactive decay (like alpha or beta decay) to transform into more stable elements. For example, Uranium-238 naturally decays over a long series into Lead-206.
- Artificial Transmutation: This is a man-made process where a stable nucleus is bombarded with high-energy particles (like neutrons or alpha particles) in a nuclear reactor or particle accelerator. This forces the nucleus to change, creating a new element. The first instance was when Ernest Rutherford bombarded nitrogen with alpha particles to create oxygen.
3. How do nuclear fission and fusion serve as examples of transmutation?
Both nuclear fission and nuclear fusion are powerful examples of transmutation because they result in the formation of new elements. In fission, a heavy, unstable nucleus (like Uranium-235) splits into two or more lighter nuclei (like Krypton and Barium), which are different elements from the original. In fusion, two light nuclei (like isotopes of hydrogen) combine under extreme temperature and pressure to form a heavier nucleus (like Helium). In both cases, the identity of the element changes, which is the definition of transmutation.
4. What is the key difference between the historical concept of alchemy and the modern science of transmutation?
The primary difference lies in their foundation and method. Alchemy was a pre-scientific, philosophical tradition that aimed to turn base metals like lead into gold, often guided by mysticism and empirical trial-and-error without an understanding of atomic structure. In contrast, modern transmutation is a scientifically proven process based on nuclear physics. It involves precise, predictable changes to the atomic nucleus and is governed by fundamental laws of conservation, something the alchemists were unaware of.
5. What are the fundamental principles used to balance a nuclear transmutation equation?
To balance a nuclear transmutation equation, two fundamental conservation laws must be applied:
- Conservation of Mass Number (A): The sum of the mass numbers (the total number of protons and neutrons) of the reactants must equal the sum of the mass numbers of the products.
- Conservation of Atomic Number (Z): The sum of the atomic numbers (the number of protons) of the reactants must equal the sum of the atomic numbers of the products. This ensures that electric charge is conserved.
6. Can an element be transmuted into any other element?
Theoretically, it is possible to transmute an element into another, but it is constrained by the laws of nuclear physics and energy requirements. The stability of the resulting nucleus is a major factor. Transmutations that result in highly stable nuclei are more favourable. While we can induce many transmutations artificially, converting elements into significantly heavier ones requires immense energy, and the resulting isotopes are often highly unstable and radioactive with very short half-lives.
