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Ununennium, also known as eka-francium or element 119, is a hypothetical chemical element; it has symbol Uue and atomic number 119. Ununennium and Uue are the temporary systematic IUPAC name and symbol respectively, which are used until the element has been discovered, confirmed, and a permanent name is decided upon.
The periodic table is a tabular arrangement of the chemical elements, organized by their atomic number, electron configuration, and chemical properties. It is a useful tool for understanding the patterns and trends of the elements and their interactions. Learn more about the history, structure, and significance of the periodic table on Wikipedia.
An extended periodic table theorizes about chemical elements beyond those currently known and proven. The element with the highest atomic number known is oganesson ( Z = 118), which completes the seventh period (row) in the periodic table. All elements in the eighth period and beyond thus remain purely hypothetical.
The unit of amount of substance in the International System of Units is the mole (symbol: mol), a base unit. [ 1] Since 2019, the value of the Avogadro constant NA is defined to be exactly 6.022 140 76 × 1023 mol−1. Sometimes, the amount of substance is referred to as the chemical amount or, informally, as the " number of moles " in a given ...
The mole (symbol mol) is a unit of measurement, the base unit in the International System of Units (SI) for amount of substance, a quantity proportional to the number of elementary entities of a substance. One mole contains exactly 6.022 140 76 × 1023 elementary entities (approximately 602 sextillion or 602 billion times a trillion), which can ...
Naturally occurring cadmium (48 Cd) is composed of 8 isotopes.For two of them, natural radioactivity was observed, and three others are predicted to be radioactive but their decays have not been observed, due to extremely long half-lives.
Naturally occurring cerium (58 Ce) is composed of 4 stable isotopes: 136 Ce, 138 Ce, 140 Ce, and 142 Ce, with 140 Ce being the most abundant (88.48% natural abundance) and the only one theoretically stable; 136 Ce, 138 Ce, and 142 Ce are predicted to undergo double beta decay but this process has never been observed.
115 In [n 10] [n 11] 49 66 ... 119 In 49 70 118.905845(8) ... International Union of Pure and Applied Chemistry. 19 October 2005. Half-life, spin, and isomer data ...