Radium alpha decay

Radium-226 decays by alpha emission to radon-222. Suppose that 25.0% of the energy given offby one gram of radium is converted to electrical energy. What is the minimum mass of lithium that would be needed for the voltaic cell Li Li+1 Cu2+ Cu, at standard conditions, to produce the same amount of electrical work (AG°) ... 

Radium is extremely radioactive. It glows in the dark with a faint bluish light. Radiums radioisotopes undergo a series of four decay processes each decay process ends with a stable isotope of lead. Radium-223 decays to Pb-207 radium-224 and radium-228decay to Pb-208 radium-226 decays to Pb-206 and radium-225 decays to Pb-209. During the decay processes three types of radiation—alpha (a), beta ((5), and gamma (y)—are emitted. 

ISOTOPES There are 37 isotopes of radon. All are radioactive. None are stable. They range in mass numbers from Rn-196 to Rn-228. Their half-lives range from a few microseconds to 3.8235 days for Rn-222, which is the most common. It is a gas that is the result of alpha decay of radium, thorium, or uranium ores and underground rocks. 

The parent nucleus was radium, and an alpha particle was produced. Alpha decay lowers the mass number by 4 and... 

ACTINON. The name of the isotope of radon (emanation), which occurs in the naturally occurring actinium, series being, produced by alpha-decay of actinium X, which is itself a radium isotope. Achnon has an atomic number of 86, a mass number of 219, and a half-life of 3.92 seconds, emitting an alpha particle to form polonium-215 (Actinium A). See also Chemical Elements and Radioactivity. 

The radium isotope of mass number 226 occurs in the uranium (2n + 2) alpha-decay series. Its half-life is 1.620 years, and it yields radon-222 by o-disintegration. Other naturally occurring isotopes of radium are "v Ra in... 

Alpha decay is nuclear decomposition such that one of the products of the reaction is an alpha (a) particle, 4He. In an example of alpha decay, radium-222 decomposes to form radon-218 plus an alpha particle ... 

One example of alpha particle emission is the decay of radium. This decay is shown in the following equation ... 

Marie Curie discovered the element polonium, Po, in 1898. She named polonium after Poland, her homeland. Curie won two Nobel Prizes, one in Physics (1903) for sharing in the discovery of radioactivity, and one in Chemistry (1911) for the discovery of radium, which has been used to treat cancer. Radium-226 undergoes alpha decay to yield radon-222. 

Note also that a new element, radon (Rn), is created as a result of the alpha decay of the unstable radium-226 nucleus. The type of equation shown above is known as a nuclear equation because it shows the atomic number and mass number of the particles involved. It is important to note that both mass number and atomic number are conserved in nuclear equations. The accounting of atomic numbers and mass numbers below shows that they are conserved. 

A radium-226 nucleus undergoes alpha decay to form radon-222. What is the charge on the alpha particle that Is emitted ... 

The long-lived isotope of radium, Ra, decays hy alpha particle emission to its daughter radon, Rn, with a half-life of 1622 years. The energy of the alpha particle is 4.79 MeV. Suppose 1.00 g of Ra, freed of all its radioactive progeny, were placed in a calorimeter that contained 10.0 g of water, initially at 25°C. Neglecting the heat capacity of the calorimeter and heat loss to the surroundings, calculate the temperature the water would reach after 1.00 hour. Take the specific heat of water to be 4.18 J g. ... 

As the a particle loses energy, it picks up electrons and eventually becomes 4He in the atmosphere. As the helium nucleus contains two protons and two neutrons the nucleus Z number changes from that of U (Z = 92) to Th (Z = 90), while the mass number decreases by 4. Another source of helium is the alpha decay of radium (Ra) ... 

When Fermi s group analyzed the products of the neutron bombardment, it appeared to them that radium had been produced, especially since they had no reason to even suspect that barium could be a product. Since radium is the daughter element formed by two successive alpha decays of a uranium atom, they decided their quest for a transuranium element was unsuccessful. Subsequently, Otto Hahn (1879-1968), Fritz Strassmann (1902-80), and Lise Meitner (1878-1968), all from Germany, reinterpreted the results to show that it was not radium atoms that had been formed, but barium atoms instead from the nuclear fission of uranium. Thus, Fermi and his group just missed discovering fission. 

Write a nuclear reaction to represent radium-226 decaying to radon-222 plus an alpha particle. 

Alpha decay involves the loss of an a particle ( He) from a nucleus. For each a particle emitted by the parent nucleus, A decreases by 4 and Z decreases by 2. Every element that is heavier than lead (Pb Z = 82), as well as a few lighter ones, exhibits a decay. For example, radium undergoes a decay to yield radon (Rn Z = 86) ... 

There are several differenf fypes of radioactive decay. One frequently observed decay process involves production of an alpha (a) particle, which is a helium nucleus (2He). Alpha-particle production is a very common mode of decay for heavy radioactive nuclides. For example, gRa, radium-222, decays by a-particle production to give radon-218. 

Alpha radiation The radiation that was deflected toward the negatively charged plate was named alpha radiation. It is made up of alpha particles. An alpha particle contains two protons and two neutrons, and thus has a 2+ charge, which explains why alpha particles are attracted to the negatively charged plate as shown in Figure 4.21. An alpha particle is equivalent to a helium-4 nucleus and is represented by 2He or a. The alpha decay of radioactive radium-226 into radon-222 is shown below. 

Predict the nuclear equation for the alpha decay of radium-226 used on the tips of older lightning rods. 

What product is formed when radium-226 undergoes alpha decay ... 

Decay of which nucleus will lead to the following products (a) bismuth-211 by beta decay (b) chromium-50 by positron emission (c) tantalum-179 by electron capture (d) radium-226 by alpha decay ... 

Another element that contributes to our background radiation, and hence to our risks of radiation-caused damage, is radon. Radon-222, the most common isotope of radon, is radioactive, with a half-life of 3.82 days. It is a product of the uranium decay series (see Figure 13.5) and results from the alpha decay of radium-226. 

Just a year later three radiochemists from Vienna— S. Meyer, G. Hess, and F. Paneth—studied actinium-227, an isotope belonging to the family of uranium-235. They repeated their experiments and at last their sensitive instruments detected alpha particles of unknown origin. Alpha particles emitted by various isotopes have specific mean paths in air (of the order of a few centimetres). The mean path of the alpha particles in the experiments of the Austrian scientists was 3.5 cm. No known alpha-active isotope had such mean path of alpha particles. The scientists from the Vienna Radium Institute concluded that these particles were the product of alpha decay of the typically beta-active actinium-227. A product of this decay had to be an isotope of element 87. 

Artificial synthesis of francium is much more difficult and less reliable method than extraction of francium as a product of decay of natural actinium. But natural actinium is rare. What to do A current method is to irradiate the main isotope of radium with a mass number of 226 (its half-life is 1 622 years) with fast neutrons. Radium-226 absorbs a neutron and converts into radium-227 with a half-life of about 40 min. Its decay gives rise to pure actinium-227 whose alpha decay in its turn produces francium-223. 

This analysis can, for example, be applied to multistep radioactive decay reactions and to isomerization reactions. In such multistep processes, every step is by definition a first-order process. An example of multistep radioactive decay is the Actinium series (see Lederer et ah, 1968), in which Bi alpha-decays to ° T1, which beta-decays to ° Pb with respective half-lives of 2.14 and 4.77 min. Therefore, in this two-step consecutive process, k J ki =/9 = 2.14/4.77 = 0.449, very close to the Acme point. Similarly, in the Radium series, Pb beta-decays to which beta-decays to Po, which then alpha-decays very rapidly (with a half-life of only 0.16 ms) to ° Pb. This multistep decay can be closely approximated by two steps, the first with a half-life of 27 min, the second with a half-life... 

Alpha particles are composed of two protons and two neutrons and are ejected during alpha decay of heavy nuclei. The loss of mass leads to a nucleus that is more stable. Common alpha emitters are isotopes of uranium, radium, polonium, and plutonium. An alpha particle can also be thought of as a fully ionized helium-4 nucleus. Figure 25.1 depicts... 

Radium-226 undergoes alpha decay to radon-222 with a half-life of 1.60 X 10 yr. A sample of radium ore initially contains 275 g of radium-226, (a) How many grams of Ra-226 are left in the sample after 4.80 X 10 yr (b) How many alpha emissions would have occurred in this time (Hint The number of emissions equals the number of atoms that decayed.)... 

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