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Yttrium is a chemical element; it has symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and has often been classified as a "rare-earth element". [8] Yttrium is almost always found in combination with lanthanide elements in rare-earth minerals and is never found in nature as a free ...
This is a list of chemical elements and their atomic properties, ordered by atomic number (Z). Since valence electrons are not clearly defined for the d-block and f-block elements, there not being a clear point at which further ionisation becomes unprofitable, a purely formal definition as number of electrons in the outermost shell has been used.
Natural yttrium (39 Y) is composed of a single isotope yttrium-89. The most stable radioisotopes are 88 Y, which has a half-life of 106.6 days, and 91 Y, with a half-life of 58.51 days. All the other isotopes have half-lives of less than a day, except 87 Y, which has a half-life of 79.8 hours, and 90 Y, with 64 hours.
Fission product yields by mass for thermal neutron fission of U-235 and Pu-239 (the two typical of current nuclear power reactors) and U-233 (used in the thorium cycle). This page discusses each of the main elements in the mixture of fission products produced by nuclear fission of the common nuclear fuels uranium and plutonium.
Of the 26 "monoisotopic" elements that have only a single stable isotope, all but one have an odd atomic number—the single exception being beryllium. In addition, no odd-numbered element has more than two stable isotopes, while every even-numbered element with stable isotopes, except for helium, beryllium, and carbon, has at least three.
A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...
A table or chart of nuclides is a two-dimensional graph of isotopes of the elements, in which one axis represents the number of neutrons (symbol N) and the other represents the number of protons (atomic number, symbol Z) in the atomic nucleus. Each point plotted on the graph thus represents a nuclide of a known or hypothetical chemical element.
Neutrons do not affect the electron configuration. Atoms of a chemical element that differ only in neutron number are called isotopes. For example, carbon, with atomic number 6, has an abundant isotope carbon-12 with 6 neutrons and a rare isotope carbon-13 with 7 neutrons. Some elements occur in nature with only one stable isotope, such as ...