Types of Radioactive Emissions

There are five main types of emissions alpha emission, beta emission, positron emission, electron capture, and gamma emission. Four of these produce changes in the elements undergoing decay, and the end result is a more stable atomic structure. 

These emissions result in the release of an alpha particle from the atom. Recall that an a-particle is a helium nucleus. The result in alpha decay is the atom s atomic number decreasing by two and the mass number decreasing by four. An example of an a-decay is  

Fill in the missing isotope in the reaction that follows  

Although there are two types of (3-particles ((3 and (3 ), the former is usually referred to as a positron, so we ll refer to only the (3 particle as a beta particle. In a beta emission, a beta particle is ejected from the atom. A beta particle has all of the properties of an electron (virtually massless, negative charge), yet it is created by the conversion of a neutron in the nucleus to a proton and an electron (beta particle). The proton remains in the nucleus, and the beta particle is ejected from the nucleus. An example of a beta emission is  

Notice that since the number of nucleons in the atom does not change, the mass number remains unchanged. However, the gain of a proton increases the atomic number by one (and consequently changes the element). 

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The common type of radioactive emission that does not consist of matter is the gamma ray. 

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. 

A stable nucleus remains intact indefinitely, but the great majority of nuclei are unstable. An unstable nucleus exhibits radioactivity it spontaneously disintegrates, or decays, by emitting radiation. In the next section, you ll see that each type of unstable nucleus has its own characteristic rate of radioactive decay, which can range from a fraction of a second to billions of years. This section introduces important terms and notation for nuclei, describes the common types of radioactive emissions and decay, and discusses how to predict whether and how a given nucleus will decay. 

Figure 23.1 Three types of radioactive emissions in an eiectric field. Positively charged ct particles curve toward the negative plate negatively charged (3 particles curve toward the positive plate. The curvature is greater for 3 particles because they have much lower mass. The y rays, uncharged high-energy photons, are unaffected by the field.

When a nuclide decays, it forms a nuclide of lower energy, and the excess energy is carried off by the emitted radiation. The three most common types of radioactive emission are ... 

Describe the differences between nuclear and chemical changes identify the three types of radioactive emissions and the types of radioactive decay, and know how each changes A and Z explain how a decay series leads to a stable nuclide write and balance nuclear equations use the N/Zratio to predict nuclear stability and the type of decay a nuclide undergoes ( 23.1) (SPs 23.1-23.3) (EPs 23.1-23.16)... 

The Separation of Radiation movie (eChapter 2.2) shows how three different types of radioactive emissions behave in the presence of an electric field, (a) Which of the three types of radiation does not consist of a stream of parti-... 

Summarize the nuclear changes that occur for each of the following types of radioactive emissions by determining the algebraic expressions (using a or z) that would be placed in the boxes for the mass number and the atomic number that would complete the nuclear equation. 

While Curie focused her work on discovering the different kinds of radioactive elements, Ernest Rutherford and others focused on characterizing the radioactivity itself. These scientists found that the emissions were produced by the nuclei of radioactive atoms. These nuclei were unstable and would emit small pieces of themselves in the form of electromagnetic radiation to gain stability. These were the particles that Becquerel and Curie detected. There are several different types of radioactive emissions alpha (a) rays, beta (/3) rays, gamma (y) rays, and positrons. 

When a nuclide of one element decays, it emits radiation and usually changes into a nuclide of a different element. The three natural types of radioactive emission are... 

Figure 23.1 How the three types of radioactive emissions behave in an electric field.

Identify the three types of radioactive emissions and the types of radioactive decay, and know how each changes A and Z explain how a decay series leads to a stable nnclide write and balance nuclear equations nse the... 

Rutherford used alpha particles in his investigation of the atom (Section 5.3). Alpha particles are one of the three types of radioactive emissions discussed in the next section. 

Define radioactivity. Name, identify from a description, or describe three types of radioactive emissions. 

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