What is the radioactive isotope of Cerium?
26943
It appears that the question period has expired.  If you have received an answer that meets your needs, please choose one of those as a 'best answer.'  If you haven't received a good answer for your question, you may want to consider the following,\n\n1) Re-post your question.  Newer questions get more activity on Yahoo! Answers than old ones.\n2) If you do re-post your question, consider why it wasn't answered the first time.  Could it be more specific?  Could it be worded better? Were there grammatical or spelling errors? Was it in the best category?\n\nIf it doesn't seem likely that re-posting your question will help you, then here's a listing of my favorite 'answer sites'.  Maybe one of them will help you.\n\nAnswers.com http://www.answers.com/\nBartleby http://www.bartleby.com/\nYahoo Reference http://education.yahoo.com/reference/\nHowStuffWorks http://www.howstuffworks.com/\nWikipedia http://en.wikipedia.org/wiki/Main_Page\n\nSince I really haven't answered your question, it is not necessary to give me any points.  Regards.
612990
At the bottom of the perodic table...\n\nThey are technetium (at. no. 43), which was the first element to be synthesized, promethium (at. no. 61), astatine (at. no. 85), francium (at. no. 87), and the transuranium elements (at. no. 93 and beyond in the periodic table). Some of these elements have since been shown to exist in minute amounts in nature, usually as short-lived members of natural radioactive decay series (see radioactivity).\n\nThe synthetic elements through at. no. 100 (fermium) are created by bombarding a heavy element, such as uranium or plutonium, with neutrons or alpha particles. The synthesis of the transfermium elements (elements with at. no. 101 or greater) is accomplished by the fusion of the nuclei of two lighter elements. Elements 101 through 106 were first produced by fusing the nuclei of slightly lighter elements, such as californium, with those of light elements, such as carbon. Elements 107 through 112 were first produced by fusing the nuclei of medium-weight elements, such as bismuth or lead, with those of other medium-weight elements, such as iron, nickel, or zinc. Element 114 was first produced by fusing the nuclei of plutonium and calcium and subsequently by fusing the nuclei of lead and krypton, as was element 116. Element 115 was produced by bombarding americium with calcium, and element 113 resulted from the radioactive decay of element 115. The claim by Lawrence Berkeley National Laboratory to have created element 118 has been retracted.)\n\nThe transfermium elements are produced in very small quantities (one atom at a time), and identification is therefore very difficult because of half-lives ranging from minutes to milliseconds and the need to identify the products by methods other than known chemical separations. This has led to controversy over reported discoveries and over the naming of the elements. It has been predicted that one isotope of element 114—containing 114 protons and 184 neutrons—would be very stable because its nucleus would have a full complement of protons and neutrons. Termed an “island of stability,” its half-life might be measured in years. However, none of the three isotopes of element 114 synthesized as yet have as many as 184 neutrons, and their half-lives are still in the millisecond range.
786305
Isotopes are atoms with the 'wrong' number of nutrons, or no-charge particles, in the nucleus. The non-isotope form of the element contains the same number of nutrons as it has protons. \nIE: carbon\nCarbon usually contains 6 protons and 6 nutrons, each weighing one atomic mass unit (AMU), for a total of 12 AMU. It's refered to, therefore, as Carbon 12.\nThe radioactive carbon isotope you hear about that's used for finding the age of old things people dig up is Carbon 14. To be carbon, it has to have 6, and only 6, protons. To weigh 14 AMU, it needs an extra 2 nutrons. 6+6+2=14\n\nIsotopes are written as isotope mass number over nonisotope mass number (as a fraction, not reduced) infront of the atomic symbol.\n\n14\n----- C = carbon 14 \n12
419931
Rather than radioactive element, let's call it a radioactive isotope.  Why?  Because a radioactive element can decay and still be the same element but have fewer neutrons.  As other posters sort of explained, if an isotope is radioactive then half of it should become something else in the specific half life time.  It could still be the same element, or it might be a lighter element.  Read the link about carbon dating and you might understand how this is useful.
409660
235 Uranium + 1 neutron --> 140 Cesium + 93 Rubidium + 3 neutrons
290665
3.45×10^−25 kg = Lead-208 atom, the heaviest stable isotope known\n\ncheck here http://en.wikipedia.org/wiki/Orders_of_magnitude_(mass) good luck
93157
Isotopes are forms of an element whose nuclei have the same atomic number–-the number of protons in the nucleus--but different mass numbers because they contain different numbers of neutrons.\n\nThe word isotope, meaning at the same place, comes from the fact that all isotopes of an element are located at the same place on the periodic table.\n\nCollectively, the isotopes of the elements form the set of nuclides. A nuclide is a particular type of atomic nucleus, or more generally an agglomeration of protons and neutrons. Strictly speaking, it is more correct to say that an element such as fluorine consists of one stable nuclide rather than that it has one stable isotope.\n\nIn scientific nomenclature, isotopes (nuclides) are specified by the name of the particular element by a hyphen and the number of nucleons (protons and neutrons) in the atomic nucleus (e.g., helium-3, carbon-12, carbon-14, iron-57, uranium-238). In symbolic form, the number of nucleons is denoted as a superscripted prefix to the chemical symbol (e.g., 3He, 12C, 14C, 57Fe, 238U).\n\nSee link below for more info.
231570
Let us not forget irradiation. exposure to cesium kills all microbes in the food after it is hermetically sealed it will last indefinately at room temperature. I am not pro or con on this, just thought I would mention it.
755403
this should help\n\nhttp://en.wikipedia.org/wiki/Dysprosium
766063
It's element 94 on the Periodic Table of Elements (see URL, below).  It's radioactive because nuclei of Plutonium atoms give off alpha and beta particles and gamma radiation in a process of radioactive decay.  The Wikipedia article on radioactive decay explains this well (URL below).
730866
They are different elements. \n\nNo element of higher atomic number than uranium (92) occurs naturally because they are all radioactive and decay over time.\n\nPlutonium is a transuranic element atomic number 94 that is a by product from nuclear reactors.\n\nOnly some isotopes of uranium are fissile (U 238 is stable). Plutonium is always fissile, and so is more useful and more potent in atomic weapons.
157223
helium neon argon krypton xenon radon\nyou probably do not need to know ununoctium because it was just discovered, is radioactive, and radioactively decays in a few seconds.
678665
Which isotope?\n\nThorium-232 has a half-life of 14 billion (14x109) years, and decays by alpha emission, with accompanying gamma radiation. Thorium-232 is the top of a long decay series that contains key radionuclides such as radium-228, its direct decay product, and radon-220. \n\nTwo other isotopes of thorium, which can be significant in the environment, are thorium-230 and thorium-228. Both belong to other decay series. They also decay by alpha emission, with accompanying gamma radiation, and have half-lives of 75,400 years and 1.9 years, respectively
715465
1) After k half-lives, the remaining amount of Barium-131 from the m miligrams to start with is: m / 2^k (mg)\n\nIn your case, m = 10 mg and k = 3.\n\n2) Time for m miligrams of any radioactive species to decay to n miligrams is t1.\n\nHalf-life t = t1 / log(2)(m/n)\n\nIn your case, t1 = 45minutes, m = 50mg and n = 6.25mg\n\n3) Density d = p(MW)/RT\n\np = 2\nMW = 14\nR = 0.0821\nT = 273 + 127 = 400
13966
Answers:\n\n(a) Thorium-234>Proactinium-234 = -1e (beta decay)\n\n(b) Hydrogen + Hydrogen > Helium (fusion)\n\n(c) Uranium-238 > Thorium-234 + Helium-4 (alpha decay)
905264
plutonium. neptunium, mercury ,uranium
94911
Technetium is a chemical element that has the symbol Tc and the atomic number 43. Pronounced tek-nee-s(h)ee-um, the chemical properties of this silvery grey, radioactive, crystalline transition metal are intermediate between rhenium and manganese. Its short-lived isotope Tc-99m is used in nuclear medicine for a wide variety of diagnostic tests. Tc-99 is used as a gamma ray-free source of beta particles, and its pertechnetate ion (TcO4-) could find use as an anodic corrosion inhibitor for steel.\n\nDmitri Mendeleev predicted many of the properties of element 43, which he called ekamanganese, well before its actual discovery (see Mendeleev's predicted elements). In 1937 its isotope Tc-97 became the first element to be artificially produced, hence its name (from the Greek τεχνητος, meaning "artificial"). Most technetium produced on Earth is a by-product of fission of uranium-235 in nuclear reactors and is extracted from nuclear fuel rods. No isotope of technetium has a half-life longer than 4.2 million years (Tc-98), so its detection in red giants in 1952 helped bolster the theory that stars can produce heavier elements. On earth, technetium occurs naturally only in uranium ores as a product of spontaneous fission; the quantities are minute but have been measured.\n\nNotable characteristics\nTechnetium is a silvery-grey radioactive metal with an appearance similar to platinum. However, it is commonly obtained as a grey powder. Its position in the periodic table is between rhenium and manganese and as predicted by the periodic law its properties are intermediate between those two elements. This element is unusual among the lighter elements because it has no stable isotopes and is therefore extremely rare on Earth.\n\nThe metal form of technetium slowly tarnishes in moist air. Its oxides are TcO2 and Tc2O7. Under oxidizing conditions technetium (VII) will exist as the pertechnetate ion, TcO4-. Common oxidation states of technetium include 0, +2, +4, +5, +6 and +7. When in powder form technetium will burn in oxygen. It dissolves in aqua regia, nitric acid, and concentrated sulfuric acid, but it is not soluble in hydrochloric acid. It has characteristic spectral lines at 363 nm, 403 nm, 410 nm, 426 nm, 430 nm, and 485 nm.\n\nThe metal form is slightly paramagnetic, meaning its magnetic dipoles align with external magnetic fields even though technetium is not normally magnetic. The crystal structure of the metal is hexagonal close-packed. Pure metallic single-crystal technetium becomes a type II superconductor at 7.46 K; irregular crystals and trace impurities raise this temperature to 11.2 K for 99.9% pure technetium powder. Below this temperature technetium has a very high magnetic penetration depth, the largest among the elements apart from niobium.\n\n\nApplications\n\nNuclear medicine\nTc-99m ("m" indicates that this is a metastable nuclear isomer) is used in radioactive isotope medical tests, for example as a radioactive tracer that medical equipment can detect in the body. It is well suited to the role because it emits readily detectable 140 keV gamma rays, and it has a short half-life of 6.01 hours (meaning it has almost completely decayed to Tc-99 in 24 hours). In the book Technetium by Klaus Schwochau, 31 different radiopharmaceuticals based on Tc-99m are listed for imaging and functional studies of the brain, myocardium, thyroid, lungs, liver, gallbladder, kidneys, skeleton, blood and tumors.\n\nImmunoscintigraphy incorporates Tc-99m into a monoclonal antibody, an immune system protein capable of binding to cancer cells. A few hours after injection, medical equipment is used to detect the gamma rays emitted by the Tc-99m; higher concentrations indicate where the tumor is. This technique is particularly useful for detecting hard to find cancers, such as those affecting the intestine. These modified antibodies are sold by the German company Hoechst under the name Scintium.\n\nWhen Tc-99m is com