The student is expected to describe the characteristics of alpha, beta, and gamma radiation AND describe radioactive decay process in terms of balanced nuclear equations AND compare fission and fusion reaction.
The radiation emitted by an element can be characterized as alpha, beta or gamma radiation. Alpha radiation consists of helium nuclei with a 2+ charge and little penetrating power. Beta radiation consists of electron particles with a 1- charge with more penetrating power. Gamma radiation consists of high-energy photons with a neutral charge and very high penetrating power.
A balanced nuclear equation may be used to describe the process of radioactive decay during alpha and beta emissions, or transmutations. The equation is balanced if the sum of the mass numbers and atomic numbers are equal on both sides of the equation.
Nuclear fission occurs when large, unstable atoms (usually isotopes of uranium and plutonium) are split by a neutron into smaller, more stable atoms. Nuclear fusion is the opposite of fission and occurs when smaller atoms fuse together to form larger, more stable atoms.
Radiation
Radiation is the phenomenon that occurs when energy travels and is transmitted in particles or waves. In general, the radiation emitted by an element can be characterized as alpha, beta, or gamma radiation.
Alpha radiation consists of helium nuclei (two protons and two neutrons), a +2 charge, and little penetrating power. Alpha particles interact heavily with substances. Even a thin piece of paper could stop its traveling. Thus, it cannot travel through tissues of human body.
Alpha decay occurs when an atomic nucleus emits an alpha particle, which results in the transformation of an atom to one with a mass number 4 less and an atomic number that is 2 less. An example is the alpha decay of plutonium-240 into uranium-236. The alpha decay process results in nuclear transmutation, which is the creation of an atom of a new element.
Beta radiation consists of electron particles with a -1 charge and greater penetrating power. The beta particles consist of energetic electrons. They can travel through paper, but not through an aluminum plate.
Beta decay occurs when the neutron-to-proton ratio is too great in the nucleus, causing instability. The result is the transformation of a neutron into a proton and an electron. An example is the beta decay of carbon-14 into nitrogen-14. Beta decay also results in nuclear transmutation.
Gamma radiation consists of high-energy photons with a neutral charge and very high penetrating power. Gamma rays are difficult to stop due to their high levels of energy. You might have seen a very thick lead door at a radiology department in a hospital. The lead door stops gamma radiation, although some rays may still be able to penetrate the door.
Gamma decay does not result in nuclear transmutation. Instead, gamma decay occurs when the energy contained within the nucleus of an atom is too high. The result is the reduction of the energy state and the emission of a high energy photon. An example of gamma decay is the release of a gamma photon from an unstable He-3 atom.
Radiation Penetration
Each type of radiation varies in its ability to penetrate matter.
Balanced Nuclear Reaction Equation
Equations can be written to represent the reactants and products in a nuclear reaction during alpha emissions, beta emissions, or transmutation. Coefficients are used to indicate the numbers of each reactant and product to create a balanced equation for any nuclear reaction. In this way, nuclear reactions are like chemical reactions. To balance equations for nuclear reactions, one needs to know the atomic numbers and mass numbers of the atomic symbols representing nuclei. The equation is balanced if the sum of the mass numbers and atomic numbers are equal on both sides of the equation.
The conservation laws will be needed to carry out the equation balancing, such as conservation of mass, conservation of energy, and conservation of electric charge. That is, if an atom loses mass, the lost mass should appear in another equivalent form, as either mass or energy.
Nuclear Fission
Nuclear fission occurs when large, unstable atoms (usually isotopes of uranium and plutonium) are split by a neutron into smaller, more stable atoms. During this process, huge amounts of energy are generated.
Nuclear Fusion
Nuclear fusion is the opposite of fission. Nuclear fusion occurs when smaller atoms fuse together to form larger, more stable atoms. The sunshine we enjoy every day comes from the nuclear fusion that occurs in the Sun millions of miles away. Another example includes the hydrogen bomb. The reaction that occurs is based on nuclear fusion, which releases even more energy than a fission bomb.