Nuclear reactions transmutation

Nuclear reactions usually involve the transmutation of elements. 

Fig. 17.7), is therefore the nucleus of an atom of a different element. For example, when a radon-222 nucleus emits an a particle, a polonium-218 nucleus is formed. In this case, a nuclear transmutation, the conversion of one element into another, has taken place. Another important difference between nuclear and chemical reactions is that energy changes are very much greater for nuclear reactions than for chemical reactions. For example, the combustion of 1.0 g of methane produces about 52 kj of energy as heat. In contrast, a nuclear reaction of 1.0 g of uranium-235 produces about 8.2 X 10 kj of energy, more than a million times as much. 

Nuclear reactions may result in the formation of different elements. The transmutation of a nucleus can be predicted by noting the atomic numbers and the mass numbers in the nuclear equation for the process. 

Radon-222 is an unstable nuclide that has been detected in the air of some homes. Its presence is a concern because of high health hazards associated with exposure to its radioactivity. Gaseous radon easily enters the lungs, and once it decays, the products are solids that remain embedded in lung tissue. Radon-222 transmutes to a stable nuclide by emitting a and P particles. The first four steps are a, a, P, p. Write this sequence of nuclear reactions and identify each product. 

This results in the transmutation of parent element X into daughter Y, which has an atomic number two less than X. The particular isotope of element Y which is formed is that with an atomic mass of four less than the original isotope of X. Note that, as in chemical reactions, these nuclear reactions must be numerically balanced on either side of the arrow. Many of the heavy elements in the three naturally occurring radioactive decay chains (see below) decay by a-emission. 

Neither californium nor its compounds are found in nature. All of its isotopes are produced artificially in extremely small amounts, and all of them are extremely radioactive. All of its isotopes are produced by the transmutation from other elements such as berkelium and americium. Following is the nuclear reaction that transmutates californium-250 into cahfornium-252 Cf + (neutron and A, gamma rays) — Cf + (neutron and A, gamma rays) —> Cf. 

The nuclear reaction involving the bombardment of curium with calcium that directly produced element 116 occurred on December 6, 2000, at the Joint Institute for Nuclear Research in Dubna, Russia, in cooperation with personnel of the Lawrence-Livermore Berkeley Group. This nuclear reaction resulted in the production of a few atoms of the isotope ununhexium-292, which has a half-life of 0.6 milliseconds and emits four neutrons. Uuh-292 is also the most stable isotope of element 116 as it continues to decay into elements with Z numbers of 114, 112, 110, 108, and 106, plus emitting four alpha particles for each transmutation. (Z numbers are the number of protons in the nuclei of atoms.)... 

The story of the Sun, and indeed of any star, centres around the age-old struggle between the nuclear furnace and gravity. The pressure due to heat, or rather heat gradient, fights back against collapse and a masterful equilibrium is achieved. The vocation of the perfect star is to burn, in the nuclear sense, that is, to transmute elements in nuclear reactions. 

Transmutation The changing of one element into another by a nuclear reaction or series of reactions. Example the transmutation of uranium-238 into plutonium-239 by absorption of a neutron. 

TRANSMUTATION. The natural or artificial transformation of atoms of one element into atoms of a different element as the result of a nuclear reaction. The reaction may be one in which two nuclei interact, as in the formation of oxygen from nitrogen and helium nuclei (/3-particles), or one in which a nucleus reacts widi an elementary particle such as a neutron or proton. Thus, a sodium atom and a proton form a magnesium atom. Radioactive decay, e.g., of uranium, can be regarded as a type of transmutation. The first transmutation was performed bv the English physicist Rutherford in 1919. 

When using an HDCC accelerator, the required electric potential for having the same nuclear events is dramatically reduced. Note that for the maximum reaction rates for the D-D nuclear events, the maximum occurs at about 272 Volts (lower x-axis label). Some of the desired nuclear reactions to stabilize (transmute) specific highly radioactive species into stable elements will, of course, require that the combined HDCC be accelerated using potentials up to 70 keV. 

In order to end up with an element that was not in the reactants, the particles in the nucleus of an atom—the protons and neutrons—would have to change. This is a different type of reaction, called a nuclear reaction. Some nuclear reactions occur naturally in elements that are described as radioactive. The nuclei of radioactive elements are unstable. Since they are unstable, they can fall apart and give off subatomic particles. Eventually, through a process called radioactive decay, these unstable elements are transformed into a stable (non-radioactive) element. When an atom of one element is changed into an atom of another element through a nuclear reaction, it is called transmutation. 

Transmutation The conversion of one element into another as the result of a nuclear reaction. 

Through the use of alpha particles, neutrons, and other particles, many nuclear reactions have been induced since Rutherford s demonstration of the first transmutation. Examples of several different types of nuclear reactions follow, but no effort is made here to illustrate all the types that are known to occur. An additional example of a nuclear reaction involving bombardment by means of alpha particles is found in the production of radioactive carbon of mass 14 ... 

In most cases nuclear reactions result in a nuclear transmutation from one element to another. Transmutation was originally connected to the mythical "philosopher s stone" of alchemy that could turn cheaper elements into gold. When Frederick Soddy and Ernest Rutherford first recognized that radioactive decay was changing one element into another, Soddy remembered saying, "Rutherford, this is transmutation " Rutherford replied, "Soddy, don t call it transmutation. They ll have our heads off as alchemists."... 

In almost all of the previous examples, we have looked at nuclear reactions that occur by spontaneous decay. There are other types of nuclear reactions that can occur, known as transmutation reactions. These reactions can be induced by forcing a reaction between the nucleus of an element and nuclear particles (such as neutrons), or nuclei. Ernest Rutherford carried out the first transmutation by bombarding nitrogen-14 nuclei with alpha particles. This resulted in the production of oxygen-17 and a proton, as shown below ... 

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