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A metalloid is a chemical element which has a preponderance of properties in between, or that are a mixture of, those of metals and nonmetals.The word metalloid comes from the Latin metallum ("metal") and the Greek oeides ("resembling in form or appearance"). [1]
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 ...
Metal ions and metallic compounds are often used in medical treatments and diagnoses. [18] Compounds containing metal ions can be used as medicine, such as lithium compounds and auranofin . [ 19 ] [ 20 ] Metal compounds and ions can also produce harmful effects on the body due to the toxicity of several types of metals. [ 18 ]
A heavy, silvery d-block element, mercury is the only metallic element that is known to be liquid at standard temperature and pressure; [a] the only other element that is liquid under these conditions is the halogen bromine, though metals such as caesium, gallium, and rubidium melt just above room temperature. [b]
The following list identifies in rank order the possible biological roles of the chemical elements, ranging from a score of 5 for elements essential to all living things, to a score of 1 for elements that have no known effects on living things. There are also letter scores for special functions of the elements.
2 H 2 [NbOF 5] + 10 NH 4 OH → Nb 2 O 5 ↓ + 10 NH 4 F + 7 H 2 O. Several methods are used for the reduction to metallic niobium. The electrolysis of a molten mixture of K 2 [NbOF 5] and sodium chloride is one; the other is the reduction of the fluoride with sodium. With this method, a relatively high purity niobium can be obtained.
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Arsenic is the 53rd most abundant element in the Earth's crust, comprising about 1.5 parts per million (0.00015%). [48] Typical background concentrations of arsenic do not exceed 3 ng/m 3 in the atmosphere; 100 mg/kg in soil; 400 μg/kg in vegetation; 10 μg/L in freshwater and 1.5 μg/L in seawater. [ 49 ]