Aluminum-25, radioactive decay

Aluminum also has 14 radioactive isotopes. A radioactive isotope gives off either energy or subatomic particles in order to reduce the atomic mass and become stable. When the emission produces a change in the number of protons, the atom is no longer the same element. The particles and energy emitted from the nucleus are called radiation. The process of decaying from one element into another is known as radioactive decay. 

In 1934, when bombarding aluminum with a particles, Irene Joliot-Curie (daughter of Marie and Pierre Curie) and her husband, Frederic Joliot, observed the emission of two types of particles neutrons and positrons. The Joliots observed that when bombardment by a particles was stopped, the emission of neutrons also stopped the emission of positrons continued, however. Their conclusion was that the nuclear bombardment produces 15 P, which undergoes radioactive decay by the emission of positrons. 

Sometimes the nucleus can be changed by bombarding it with another type of particle. This is referred to as induced radioactivity. In 1934, Irene Curie, the daughter of Pierre and Marie Curie, and her husband, Frederic Joliot, announced the first synthesis of an artificial radioactive isotope. They bombarded a thin piece of aluminum foil with ot-particles produced by the decay of polonium and found that the aluminum target became radioactive. Chemical analysis showed that the product of this reaction was an isotope of phosphorus. 

Samples (156) were taken from 54 reference lithic pieces that represented five rock types. These samples were analyzed at the SLOWPOKE Reactor Facility of the University of Toronto. They were irradiated for 1 min at 2 kW, or for 1 or 2 min at 5 kW (depending on their radioactivity level in preliminary tests). Upon removal from the reactor, the samples, which weighed between 0.1 and 0.3 g, were left to decay for 18 min and were counted for 5 min with a Ge(Li) y-ray detector coupled to a multichannel analyzer. Trace element concentrations were calculated with the comparator method (7). The 15 elements examined were barium, titanium, sodium, aluminum, potassium, manganese, calcium, uranium, dysprosium, strontium, bromine, vanadium, chlorine, magnesium, and silicon. The first seven of these elements were the most useful in the differentiation of major rock types. 

The development of more sensitive ways to measure levels of radioactive substances has allowed scientists to take advantage of the decay of nuclides other than carbon-14. For example, chlorine-36 can be used to date ground water, marine sediments can be dated by measuring levels of beryllium-11 and aluminum-26, and krypton-81 has been used to estimate the age of glacial ice. 

C. Neutron-Induced Activity. If nuclei capture neutrons when exposed to neutron radiation, they will, as a rule, become radioactive and then decay by emission of beta and gamma radiation over an extended period of time. Neutrons emitted as part of the initial nuclear radiation will cause activation of the weapon residues and environmental material, such as soil, air, and water. For example, a small area around ground zero may become hazardous as a result of exposure of the minerals in the soil to initial neutron radiation, due principally to neutron capture by sodium, manganese, aluminum, and silicon in the soil. This is a negligible hazard because of the limited area involved. 

Aluminum, Aluminium. Al at. wt 26.98154 at. no. 13 valence 3. One naturally occurring isotope nAI. In addition, six radioactive isotopes and one isomer are known the most important, MAI (found in meteors), decays with emission of 0+ and >-radiation. Tw 7.4 X 10s years. One of the most abundant metals in earth s crust 8.8 % by wt occurs in nature primarily in combination with silica, also as oxide (see Aluminum Silicate Aluminum Oxide). First obtained in impure form by Oersted in 1825 prepd as metal powder by Wohler in 1827. Reviews of aluminum, its alloys and compds Brandt. Aluminum and Aluminum Alloys" in Prac. Met. Soc. Conf. Vol. 40. E. D. Verink, Ed. (Gordon Breach, New York, 1966) Aluminum. 3 Vols, K. R. Van Horn, Ed. (American Society for Metals, Metal Park, Ohio. 1967) Wade, Bannister. "Aluminum, Gallium. Indium and Thallium in Comprehensive Inorganic Chemistry, Vol, 1, J. C. Bailar, Jr. et al.. Eds. (Pergamon Press, Oxford, 1973) pp 993-1064. 

Irene Joliot-Curie (daughter of Pierre and Marie Curie) and her husband Frederic Joliot-Curie observed that when aluminum-27 is bombarded with alpha particles, neutrons and positrons (positive electrons) are emitted as part of the products. When the source of alpha particles is removed, neutrons cease to be produced, but positrons continue to be emitted. This observation suggested that the neutrons and positrons come from two separate reactions. It also indicated that a product of the first reaction is radioactive. After further investigation, they discovered that, when aluminum-27 is bombarded with alpha particles, phosphorus-30 and neutrons are produced. Phosphorus-30 is radioactive, has a half-life of 2.5 minutes, and decays to silicon-30 with the emission of a positron. The equations for these reactions are... 

In 1933, a nuclear bombardment reaction was used to produce the first artificial radioactive isotope. Irene and Frederic Joliot-Curie found that aluminum bombarded with alpha particles produces phosphorus-30, which decays by enutting positrons. The... 

The world press was initially captivated by the beautiful young Polish woman who shared the 1903 Nobel Prize in physics with Henri Becherel and Pierre Curie and she distributed the prize money to acquaintances and students. She and Pierre did not realize the effect that the radioactivity had on their health and in 1906 a weakened Pierre walked in front of a horse carriage and was killed. The Curies had two daughters before Pierre died and one daughter, Irene Joliot-Curie, was also awarded a Nobel Prize in chemistry in 1935 for discovering that aluminum became radioactive when bombarded with alpha particles. Note that the decay of radium can provide energetic... 

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