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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.
Since a nucleus with an odd number of protons is relatively less stable, odd-numbered elements tend to have fewer stable isotopes. 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 ...
It is considered a monoisotopic element and it has a standard atomic weight of 22.989 769 28(2). Sodium has two radioactive cosmogenic isotopes (22. Na, with a half-life of 2.6019 (6) years; [nb 1] and 24. Na, with a half-life of 14.9560 (15) h). With the exception of those two isotopes, all other isotopes have half-lives under a minute, most ...
A chemical element is a chemical substance that cannot be broken down into other substances by chemical reactions. The basic particle that constitutes a chemical element is the atom. Elements are identified by the number of protons in their nucleus, [1] known as the element's atomic number. [2] For example, oxygen has an atomic number of 8 ...
The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows (" periods ") and columns (" groups "). It is an icon of chemistry and is widely used in physics and other sciences. It is a depiction of the periodic law, which states that when the elements are arranged in order ...
Studies have also predicted that due to increasing electrostatic forces, oganesson may have a semibubble structure in proton density, having few protons at the center of its nucleus. [130] [131] Moreover, spin–orbit effects may cause bulk oganesson to be a semiconductor, with a band gap of 1.5 ± 0.6 eV predicted.
Hassium is a synthetic chemical element; it has symbol Hs and atomic number 108. It is highly radioactive: its most stable known isotopes have half-lives of approximately ten seconds. [ a ] One of its isotopes, 270 Hs, has magic numbers of protons and neutrons for deformed nuclei, giving it greater stability against spontaneous fission.