Evidence Of Transmutation In Nuclear Reactions Unveiling The Transformation Of Curium Into Plutonium

In the realm of nuclear chemistry, nuclear transmutation stands as a fascinating phenomenon. It involves the transformation of one element into another. This transformation occurs through nuclear reactions, typically involving the bombardment of a nucleus with subatomic particles or other nuclei. A classic example of this is represented by the nuclear equation: ${}_{96}^{242}Cm \rightarrow {}_{94}^{238}Pu + {}_2^4He$. This equation illustrates the decay of Curium-242 into Plutonium-238 and an alpha particle (Helium-4). To truly grasp the essence of transmutation, we need to delve into the equation's components and understand the underlying principles of nuclear conservation laws. This article aims to dissect this equation, identify the key indicators of transmutation, and clarify the conservation laws at play.

Decoding the Nuclear Equation

To decipher the evidence of transmutation within this equation, let's first break down the notation and the significance of each component. The equation is ${}_{96}^{242}Cm \rightarrow {}_{94}^{238}Pu + {}_2^4He$. Here, Cm represents Curium, Pu stands for Plutonium, and He signifies Helium. The numbers associated with each element are crucial. The superscript number (e.g., 242 in ${}_{96}^{242}Cm$) denotes the mass number, which is the total count of protons and neutrons (collectively known as nucleons) in the nucleus. The subscript number (e.g., 96 in ${}_{96}^{242}Cm$) represents the atomic number, which is the number of protons in the nucleus. The atomic number defines the element; changing the number of protons fundamentally changes the element itself. In this equation, Curium (Cm) with an atomic number of 96 transforms into Plutonium (Pu) with an atomic number of 94. This change in atomic number is the primary hallmark of nuclear transmutation. The other product of this reaction is ${}_2^4He$, which is an alpha particle. An alpha particle is essentially the nucleus of a Helium atom, consisting of 2 protons and 2 neutrons. It is a common emission in nuclear decay processes. The arrow ($\rightarrow$) in the equation indicates the direction of the nuclear reaction, showing the transformation from the initial reactant (Curium-242) to the products (Plutonium-238 and an alpha particle). The very fact that we begin with Curium and end up with Plutonium demonstrates that a transmutation event has occurred. This is because the fundamental identity of the atom has been altered.

The Defining Factor of Transmutation

The key indicator of transmutation in this equation lies in the change in the atomic number. In the given nuclear equation, ${}_{96}^{242}Cm \rightarrow {}_{94}^{238}Pu + {}_2^4He$, we observe that Curium (Cm), with an atomic number of 96, transforms into Plutonium (Pu), which has an atomic number of 94. This change in atomic number signifies a change in the number of protons within the nucleus. The number of protons defines the element. An atom with 96 protons is, by definition, Curium, while an atom with 94 protons is Plutonium. Therefore, this alteration in the number of protons unequivocally demonstrates that transmutation has taken place. This is the most direct and fundamental evidence. The emission of an alpha particle ($ {}_2^4He$) further supports this conclusion. The alpha particle carries away two protons and two neutrons from the Curium nucleus. This loss of protons is what causes the atomic number to decrease from 96 to 94, resulting in the formation of Plutonium. If the number of protons remained constant, the element would not change. For instance, the isotopes of an element have the same number of protons but different numbers of neutrons. A nuclear reaction that only changes the number of neutrons would not be considered transmutation because the element's identity remains the same. Furthermore, consider a hypothetical scenario where only an electron or a gamma ray was emitted. These emissions do not involve changes in the number of protons or neutrons. Therefore, such a reaction would not be classified as transmutation. In essence, transmutation is a fundamental change in the elemental identity of an atom, and this change is solely dictated by alterations in the number of protons within the nucleus.

Conservation Laws in Nuclear Reactions

While transmutation involves a change in the element, certain fundamental quantities must be conserved during the process. In nuclear reactions, two crucial conservation laws are at play: the conservation of nucleons and the conservation of charge. The conservation of nucleons states that the total number of nucleons (protons and neutrons) remains constant throughout the reaction. This means the sum of the mass numbers on the left side of the equation must equal the sum of the mass numbers on the right side. Let's examine our equation: ${}_{96}^{242}Cm \rightarrow {}_{94}^{238}Pu + {}_2^4He$. On the left side, the mass number is 242 (from Curium-242). On the right side, we have 238 (from Plutonium-238) and 4 (from Helium-4). Adding these, we get 238 + 4 = 242. Thus, the number of nucleons is conserved. The conservation of charge dictates that the total electric charge remains constant. In the context of nuclear reactions, this means the sum of the atomic numbers (number of protons) on the left side of the equation must equal the sum of the atomic numbers on the right side. Looking at our equation again, the atomic number on the left side is 96 (from Curium). On the right side, we have 94 (from Plutonium) and 2 (from Helium). Adding these, we get 94 + 2 = 96. So, the charge is also conserved. It is vital to recognize that while the number of atoms is not necessarily conserved (one Curium atom becomes one Plutonium atom and one Helium atom), the fundamental constituents of the nucleus, namely nucleons and charge, are conserved. This distinction highlights the difference between chemical reactions, where atoms are rearranged, and nuclear reactions, where the nuclei themselves are transformed. If either of these conservation laws were violated, it would indicate an error in the equation or a misunderstanding of the nuclear process. These laws provide a framework for understanding and predicting the outcomes of nuclear reactions.

Analyzing the Answer Choices

Now, let's analyze the given answer choices in light of our understanding of transmutation and conservation laws.

• A. The number of atoms is conserved, but the number of nucleons is not. This statement is incorrect. As we discussed earlier, the number of atoms is not conserved in nuclear transmutation. One Curium atom transforms into two atoms: a Plutonium atom and a Helium atom. More importantly, the number of nucleons is conserved, as demonstrated by the equality of mass numbers on both sides of the equation. This conservation is a cornerstone of nuclear reactions. To emphasize, the mass number represents the total number of protons and neutrons in a nucleus. If the number of nucleons were not conserved, it would imply that nucleons were either being created or destroyed, which contradicts our fundamental understanding of nuclear physics. Therefore, this option can be definitively ruled out.
• B. There is conservation of both nucleons and charge, but not atoms. This statement is the correct explanation. We've already established that the number of nucleons and charge are indeed conserved in this nuclear reaction. The mass numbers (242 = 238 + 4) and atomic numbers (96 = 94 + 2) balance on both sides of the equation, confirming these conservations. At the same time, the number of atoms is not conserved; one Curium atom becomes one Plutonium atom and one Helium atom. This is a hallmark of nuclear reactions, distinguishing them from chemical reactions where atoms are simply rearranged. Therefore, this option accurately reflects the processes occurring in the transmutation reaction.

Conclusion

In conclusion, the equation ${}_{96}^{242}Cm \rightarrow {}_{94}^{238}Pu + {}_2^4He$ exemplifies nuclear transmutation because it shows a change in the atomic number, indicating a transformation from Curium to Plutonium. The conservation of nucleons and charge is maintained throughout the reaction, while the number of atoms is not conserved. The correct answer, therefore, is that there is conservation of both nucleons and charge. This detailed analysis highlights the fundamental principles governing nuclear transmutation and the importance of understanding conservation laws in nuclear chemistry.