Nuclear equations beta decay

Write the nuclear equation for the radioactive decay of potassium-40 by beta emission. Identify the parent and daughter nuclides in the decay. 

Thorium-234 is also radioactive. When it decays, it emits a beta particle. Recall that a beta particle is an electron emitted by a neutron as the neutron transforms to a proton. So with thorium, which has 90 protons, beta emission leaves the nucleus with one fewer neutron and one more proton. The new nucleus has 91 protons and is no longer thorium now it is the element protactinium. Although the atomic number has increased by 1 in this process, the mass number (protons + neutrons) remains the same. The nuclear equation is... 

How would you write balanced nuclear equations for the alpha particle decay of radium-226 and the beta particle decay of iodine-131 ... 

In some radioactive decays, one proton is transformed into one neutron and a positively charged particle with the same mass as a beta 0") particle (or electron) is produced. Emission of this positively charged particle is known as positron emission. Positrons (antielectrons) are symbolized as P+ or e. The nuclear equation of the formation of a positron particle is i . i . o ... 

Note that in this equation the net effect of beta decay is to change a neutron into a proton. Although an electron is ejected from the nucleus, it was not part of the nuclear composition. The electron called a beta particle comes into being only when the nucleus tries to become stable, as shown here ... 

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. 

Tritium is hydrogen of mass number 3, having two neutrons and a proton in its nucleus. It is radioactive (half-life 12.4 years) in common with many isotopes having a large neutron-to-proton ratio, tritium decays with emission of an electron (called a beta ray). Such a decay can be represented by the nuclear equation (see also Chap. 27) ... 

There are three main types of radioactive decay alpha particle emission, beta particle emission, and the emission of gamma radiation. When an unstable isotope undergoes radioactive decay, it produces one or more different isotopes. We represent radioactive decay using a nuclear equation. Two rules for balancing nuclear equations are given below. 

Which nuclear equation below demonstrates beta decay ... 

Iodine-131 is used for medical treatment of thyroid problems. It decays by emission of a beta particle. Write a nuclear equation for this reaction. 

The radiation given off by iodine-131 in the form of beta particles is used to treat cancer of the thyroid gland. Write the nuclear equation to describe the decay of an iodine-131 nucleus. 

The parent nuclide of the thorium decay series is ioTh. The first four decays are as follows alpha emission, beta emission, beta emission, and alpha emission. Write the nuclear equations for this series of emissions. 

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

Write balanced nuclear equations for beta decay, positron emission, electron capture, and alpha decay processes and calculate the maximum kinetic energies of particles emitted (Section 19.2, Problems 7-18). 

Notice that transmutation of elements has occurred. An atom of carbon-14 is converted into an atom of nitrogen-14. Because the beta particle has only the mass of an electron, the mass number remains 14. Because the beta decay changes a neutron to a proton, the atomic number of the nucleus increases by one unit, from 6 to 7. The atomic number on the left side of the equation, 6, is the same as the sum on the right side of the equation (6 = 7 + ( — 1)). The nuclear equation as a whole is balanced. 

When plutonium-239 is produced from urani-um-238 in a breeder reactor, the process occurs in three steps. In the first step, uranium-238 absorbs a neutron. In the second step, a shortlived intermediate element is made through beta decay. In the third step, the plutonium-239 is produced through beta decay. Write a balanced nuclear equation for each of the three steps. 

The reason that nuclear wastes must be isolated from the environment for a very long time is that they contain relatively long-lived radioactive nuclides, such as technetium-99 with a half-life of over 2.1 x 10 years. One proposed solution is to bombard the waste with neutrons so as to convert the long lived nuclides into nuclides that decay more quickly. When technetium-99 absorbs a neutron, it forms technetium-100, which has a half-life of 16 seconds and forms stable ruthenium-100 by emitting a beta particle. Write the nuclear equations for these two changes. 

Write a balanced nuclear equation for fhe decay of each of fhe following nuclides fo produce a beta particle. 

Write the nuclear decay equation for the beta decay of iodine-131. 

Beta particles A beta particle is a very fast-moving electron that is emitted when a neutron in an unstable nucleus converts into a proton. Beta particles are represented by the symbol (3 or e. They have a 1 — charge. Their mass is so small compared with the mass of nuclei involved in nuclear reactions that it can be approximated to zero. Beta radiation consists of a stream of fast-moving electrons. An example of the beta decay process is the decay of iodine-131 into xenon-131 by beta-particle emission, as shown in Figure 24.4. Note that the mass number of the product nucleus is the same as that of the original nucleus (they are both 131), but its atomic number has increased by 1 (54 instead of 53). This change in atomic number occurs because a neutron is converted into a proton, as shown by the following equation. 

Write a balanced nuclear equation for the reaction in which oxygen-15 undergoes positron emission. 7. Thorium-229 is used to increase the lifetime of fluorescent bulbs. What type of decay occurs when thorium-229 decays to form radium-225 8. Challenge The figure at right shows one way that bismuth-212 can decay, producing isotopes A and B. a. Write a balanced nuclear equation for this decay. b. Identify the isotopes A and B that are produced. V Beta particle Bismuth-212 Alpha particle J... 

There are three forms of beta decay. One is called negatron (fi ) emission. Nega-trons are ordinary electrons that are emitted from nuclei as the result of a nuclear transformation. Negatron decay is illustrated by the symbolic equation... 

The uranium-239 then undergoes two beta decays, first to Np, and then to Pu, which is a fissionable material and the desired product. Write balanced nuclear equations for the bombardment reaction and the two beta-decay reactions. 

Potassium ion is present in foods and is an essential nutrient in the human body. One of the naturally occurring isotopes of potassium, potassium-40, is radioactive. Potassium-40 has a natural abundance of 0.0117% and a half-life ti/2 = 1.28 X 10 yr. It undergoes radioactive decay in three ways 98.2% is by electron capture, 1.35% is by beta emission, and 0.49% is by positron emission, (a) Why should we expect to be radioactive (b) Write the nuclear equations for the three modes by which decays, (c) How many °K ions are present in 1.00 g of KCl (d) How long does it take for 1.00% of the K in a sample to undergo radioactive decay ... 

In nuclear equations, reactant and product nuclei are represented by giving their mass numbers and atomic numbers, as well as their chemical symboL The totals of the mass numbers on both sides of the equation ate equah the totals of the atomic numbers on both sides are also equal There ate four common modes of radioactive decay alpha decay, which reduces the atomic number by 2 and the mass number by 4, beta emission, which increases the atomic number by 1 and leaves the mass number unchanged, positron emission and electron capture, both of which reduce the atomic number by 1 and leave the mass number unchanged. 

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