Welcome to the fourth segment of Nuclear 101. Be sure to review last week's post about the atomic structure of uranium. This week I will explain radioisotopes and begin discussing radiation**.
Not all atoms of an element are the same, some elements have isotopes. These are forms of the element with varying numbers of neutrons. Isotopes of an element have different properties and can behave differently than each other. They have the same atomic number because they maintain the same number of protons. Remember, it is the number of protons that determine the element and therefore changing the number of neutrons does not change the element. The mass number changes, however, since the more neutrons an atom has the heavier it gets. There are three isotopes of uranium: uranium-238, uranium-235, and uranium-234. Uranium-238 is by far the most common form of uranium and comprises about 99% of all natural uranium found. Uranium-238 has 146 neutrons, uranium-235 has 143, and uranium-234 has 142. The math is very simple: Isotope number [Uranium-238] minus the number of protons (the atomic number) [92] equals the number of neutrons [146] present in that isotope.
Not all atoms of an element are the same, some elements have isotopes. These are forms of the element with varying numbers of neutrons. Isotopes of an element have different properties and can behave differently than each other. They have the same atomic number because they maintain the same number of protons. Remember, it is the number of protons that determine the element and therefore changing the number of neutrons does not change the element. The mass number changes, however, since the more neutrons an atom has the heavier it gets. There are three isotopes of uranium: uranium-238, uranium-235, and uranium-234. Uranium-238 is by far the most common form of uranium and comprises about 99% of all natural uranium found. Uranium-238 has 146 neutrons, uranium-235 has 143, and uranium-234 has 142. The math is very simple: Isotope number [Uranium-238] minus the number of protons (the atomic number) [92] equals the number of neutrons [146] present in that isotope.
Isotopes can be stable or unstable. All isotopes of uranium are unstable. An uranium isotope is a radioactive isotope, or radioisotope, because it gives off radiation in the effort to stabilize itself. Radioisotopes are unstable because they do not have the correct ratio, which varies element to element, of protons and neutrons to create a strong enough binding force to hold the nucleus together. As discussed in last week's lesson, protons have a positive charge and naturally repel each other while the neutral neutrons act as a glue to hold the protons together. Unstable atoms do not have enough neutrons to contain the positive energy of the protons and thus are said to have an excess of energy. This instability can lead the nucleus to undergo a spontaneous disintegration toward a more stable form by releasing matter and energy. This process is spontaneous because it is not guaranteed the nucleus will disintegrate in each one of these atoms, but it is a statistical probability. Radioactive decay is the process in which a nucleus disintegrates. Radiation is the energy that is released during radioactive decay. A stable atom has an adequate ratio of neutrons to maintain a binding force strong enough to contain the energy released by the protons and does not go through the process of radioactive decay.
This is the first on several posts discussing radioactivity. In the next segment I will discuss radioactive decay and the difference between alpha, beta, gamma, and neutron radiation.
This is the first on several posts discussing radioactivity. In the next segment I will discuss radioactive decay and the difference between alpha, beta, gamma, and neutron radiation.
Sources:
Global Security: Radioactive Isotopes
How Stuff Works
University of Wisconsin
World-Nuclear.org
**I have no formal training in nuclear physics and will gladly accept any and all feedback and will update this series accordingly with accepted corrections.
Global Security: Radioactive Isotopes
How Stuff Works
University of Wisconsin
World-Nuclear.org
**I have no formal training in nuclear physics and will gladly accept any and all feedback and will update this series accordingly with accepted corrections.
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