Nuclear reactions beta decay

The main point here is that the case of Pm shows that while nuclear decay is usually thought of as decreasing to a lower atomic number, some reactions (beta decay, a form of electron emission) actoally increase the atomic number of the elemental species. Note that in either case, we can use... 

Dr. Hafemeister Most isotopes really can be studied just as well or better by beta decay. I can think of only one that can t—Le, potassium-40. This is a strange case because it is an odd-odd nucleus, and there are only about four odd-odd nuclei that are stable. An odd-odd nucleus means that it decays to the neighboring even-even nuclei, and in this case one cannot populate it by beta decay. However, in most cases one does just as well with beta decay, particularly since using a nuclear reaction for direct population is so expensive. It can be done, so there should be a good reason to spend the money. Radiation damage studies by these techniques are feasible and may well be useful. 

Polonium is found only in trace amounts in the Earths crust. In nature it is found in pitchblende (uranium ore) as a decay product of uranium. Because it is so scarce, it is usually artificially produced by bombarding bismuth-209 with neutrons in a nuclear (atomic) reactor, resulting in bismuth-210, which has a half-hfe of five days. Bi-210 subsequently decays into Po-210 through beta decay The reaction for this process is Bi( ) Bi — °Po + (3-. Only small commercial milligram amounts are produced by this procedure. 

Americium does not exist in nature. All of its isotopes are man-made and radioactive. Americium-241 is produced by bombarding plutonium-239 with high-energy neutrons, resulting in the isotope plutonium-240 that again is bombarded with neutrons and results in the formation of plutonium-241, which in turn finally decays into americium-241 by the process of beta decay. Both americium-241 and americium-243 are produced within nuclear reactors. The reaction is as follows Pu + (neutron and X gamma rays) —> " Pu + (neutron and X gamma rays) —> Pu—> Am + beta minus ([ -) followed by " Am—> jNp-237 + Hej (helium nuclei). 

Seventeen radioisotopes have been synthesized in nuclear reactions. Among them Kr-85 and Kr-87 have the longest half-lives of 10 and 6 % years, respectively, both undergoing beta decay. 

Protactinium-233 is produced by the beta decay of the short-lived thorium-233. Thorium-233 is obtained by neutron capture of natural thorium-232. The nuclear reactions are as follows ... 

Again, both mass and charge are conserved. Gamma emission often accompanies both alpha and beta decay, but because gamma emission does not change the parent element it is often emitted when writing nuclear reactions. 

Plutonium is a man-made element, and only infinitesimal traces occur naturally. It melts at 641°C and boils at 3330°C. 239Pu is formed in nuclear reactors by neutron capture in 238U, followed by two successive beta decays (Fig. 5.1). Further neutron captures lead to 240Pu and 241 Pu. 238Pu is formed from 239Pu by (n,2n) reactions, or from 235U by three successive neutron captures and two beta decays. Table 5.1 shows the half-lives, alpha and X-ray energies of the principal Pu isotopes. 

Taken together, these conclusions created serious problems in physical interpretation. How could neutron capture by a single isotope initiate three such different reaction processes How could the capture of just one neutron create such great instability that multiple beta decays were needed to alleviate it Nuclear isomerism was known, but how to explain the triple isomerism of 239U Worst of all, how could one account for the inherited isomerism - for several generations - in the... 

The fifth type of radioactive emission, gamma radiation, does not result in a change in the properties of the atoms. As a result, they are usually omitted from nuclear equations. Gamma emissions often accompany other alpha or beta reactions—any decay that has an excess of energy that is released. For example, when a positron collides with an electron, two gamma rays are emitted, a phenomenon usually referred to as annihilation radiation. 

O 029 Draw a chart in your notebook to show alpha decay, beta decay, gamma decay, nuclear fusion, and nuclear fission. Write a description and give an example of each type of reaction. Illustrate each example with a drawing. 

He is produced by decay of tritium generated from the neutron activation of Li and " °Ar is produced by electron capture decay of Of the xenon isotopes, Xe is produced by the spontaneous fission of and Xe is produced by beta decay of Isotopes of neon and other isotopes of argon and xenon are produced by a variety of other nuclear reactions. 

Determine whether each of the following nuclear reactions involves alpha decay, beta decay, positron emission, or electron capture. 

As you may recall, isotopes are atoms of the same element that have different numbers of neutrons. Isotopes of atoms with unstable nuclei are called radioisotopes. These unstable nuclei emit radiation to attain more stable atomic configurations in a process called radioactive decay. During radioactive decay, unstable atoms lose energy by emitting one of several types of radiation. The three most common types of radiation are alpha (a), beta ((3), and gamma (7). Table 25-2 summarizes some of their important properties. Later in this chapter you ll learn about other types of radiation that may be emitted in a nuclear reaction. 

Write a balanced nuclear equation for the reaction in which the transition metal zirconium-97 undergoes beta decay. 

All the nuclear reactions that have been described thus far are examples of radioactive decay, where one element is converted into another element by the spontaneous emission of radiation. This conversion of an atom of one element to an atom of another element is called transmutation. Except for gamma emission, which does not alter an atom s atomic number, all nuclear reactions are transmutation reactions. Some unstable nuclei, such as the uranium salts used by Henri Becquerel, undergo transmutation naturally. However, transmutation may also be forced, or induced, by bombarding a stable nucleus with high-energy alpha, beta, or gamma radiation. 

Of the various ionizing particulate radiations, the most important in terms of likelihood for human exposure are alpha particles, beta particles, protons, and neutrons. Alpha and beta particles occur as a result of the radioactive decay of unstable atoms. Neutrons generally result from nuclear reactions, such as nuclear fission (as in nuclear reactors and fission-based nuclear weapons) and charged-particle activation of target atoms (as with some accelerator-produced... 

Rutherford s work has made him known as the father of nuclear physics with his research on radioactivity (alpha and beta particles and protons, which he named), and he was the first to describe the concepts of half-life and decay constant. He showed that elements such as uranium transmute (become different elements) through radioactive decay, and he was the first to observe nuclear reactions (split the atom in 1917). In 1908 he received the Nobel Prize in chemistry for his investigations into the disintegration of the elements, and the chemistry of radioactive substances. He was president of the Royal Society (1926-30) and of the Institute of Physics (1931-33) and was decorated with the Order of Merit (1925). He became Lord Rutherford in 1931. 

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