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List of chemical elements. 118 chemical elements have been identified and named officially by IUPAC. 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]
[2] [3] [4] Lutetium (element 71) is also sometimes considered a lanthanide, despite being a d-block element and a transition metal. The informal chemical symbol Ln is used in general discussions of lanthanide chemistry to refer to any lanthanide. [5] All but one of the lanthanides are f-block elements, corresponding to the filling of the 4f ...
Chromium is the 21st [38] most abundant element in Earth's crust with an average concentration of 100 ppm. It is also the seventh most abundant element on earth. [39] Chromium compounds are found in the environment from the erosion of chromium-containing rocks, and can be redistributed by volcanic eruptions.
The chestnut-headed bee-eater ( Merops leschenaulti) is a bird in the bee-eater family, Meropidae, which is distributed in an area ranging from India, Bangladesh and Sri Lanka across Southeast Asia to Indonesia. It is 18–20 cm (7.1–7.9 in) in overall length and weighs 26–33 g (0.92–1.16 oz), with the sexes being similar in appearance.
Rare-earth elements occur in nature in combination with phosphate ( monazite ), carbonate - fluoride ( bastnäsite ), and oxygen anions. In their oxides, most rare-earth elements only have a valence of 3 and form sesquioxides (cerium forms CeO2 ). Five different crystal structures are known, depending on the element and the temperature.
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.
e. A block of the periodic table is a set of elements unified by the atomic orbitals their valence electrons or vacancies lie in. [1] The term seems to have been first used by Charles Janet. [2] Each block is named after its characteristic orbital: s-block, p-block, d-block, f-block and g-block . The block names (s, p, d, and f) are derived ...
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.