Alkaline-Earth Metal


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Alkaline-Earth Metal

 

any one of the chemical elements of the main subgroup of Group II of Mendeleev’s periodic system, comprising the calcium family: calcium, strontium, barium, and radium (beryllium and magnesium are also sometimes considered to be alkaline-earth metals). The origin of the name is related to the fact that the oxides of the alkaline-earth metals (”eerths” in alchemical terminology) were found to be alkaline in water. The outer electron shell of alkaline-earth metal atoms contains two 5 electrons; the preceding shell contains two s and six p electrons. The alkaline-earth metals exhibit an oxidation number of +2 in their compounds. They are chemically reactive, and their reactivity increases from calcium to radium. (See alsoCALCIUM; STRONTIUM; BARIUM; and RADIUM.)

References in periodicals archive ?
Fluorides and chlorides of alkaline and alkaline-earth metals are used as additions, which enable improvement of various technological and metallurgical properties of the flux (Table 1), whereby one of the main requirements to fluxes for electroslag welding (ESW) and electroslag remelting (ESR) of titanium is complete absence of oxides, because presence in flux even in small amounts of such stable oxides as [Al.
The continental biosphere has greatly speeded up the rate of erosion of the surfaces of the continents and has given it special characteristics: increase in the pressure of CO2 in the soil and the addition of organic acids and speeding up the decomposition of silicates, all of which lead to the liberation of silica and alkaline-earth metals.
Contributors from Europe and South Africa provide background on ferroalloy basics, thermodynamics, the kinetics of reduction and general processing issues, electric furnace operations, environmental issues, and other general topics, followed by the theory and technology of ferroalloys with silicon, manganese, high carbon, and chromium, and minor ferroalloys like ferronickel, tungsten, molybdenum, vanadium, niobium, titanium, zirconium, boron, and rare-earth and alkaline-earth metals.