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Aluminium (or aluminum in North American English) is a chemical element; it has symbol Al and atomic number 13. Aluminium has a density lower than that of other common metals, about one-third that of steel. It has a great affinity towards oxygen, forming a protective layer of oxide on the surface when exposed to air.
As an approximate rule, electron configurations are given by the Aufbau principle and the Madelung rule. However there are numerous exceptions; for example the lightest exception is chromium, which would be predicted to have the configuration 1s 2 2s 2 2p 6 3s 2 3p 6 3d 4 4s 2 , written as [Ar] 3d 4 4s 2 , but whose actual configuration given ...
The aufbau principle (from the German Aufbau, "building up, construction") was an important part of Bohr's original concept of electron configuration. It may be stated as: [ 13 ] a maximum of two electrons are put into orbitals in the order of increasing orbital energy: the lowest-energy subshells are filled before electrons are placed in ...
In atomic physics and quantum chemistry, the Aufbau principle (/ ˈ aʊ f b aʊ /, from German: Aufbauprinzip, lit. ' building-up principle '), also called the Aufbau rule , states that in the ground state of an atom or ion , electrons first fill subshells of the lowest available energy , then fill subshells of higher energy.
The Hall–Héroult process is the major industrial process for smelting aluminium.It involves dissolving aluminium oxide (alumina) (obtained most often from bauxite, aluminium's chief ore, through the Bayer process) in molten cryolite and electrolyzing the molten salt bath, typically in a purpose-built cell.
Aluminum-silicon phase diagram. Aluminum forms a eutectic with silicon, which is at 577 °C, with a Si content of 12.5% [7] or 12.6%. [8] Up to 1.65% Si can be dissolved in aluminum at this temperature. However, the solubility decreases rapidly with temperature. At 500 °C it is still 0.8% Si, at 400 °C 0.3% Si and at 250 °C only 0.05% Si.
This image is a derivative work of the following images: File:Electron_shell_013_Aluminium.svg licensed with Cc-by-sa-2.0-uk . 2006-04-17T16:53:44Z File Upload Bot (Pumbaa80) 800x860 (2032 Bytes) * '''Description:''' Electron shell diagram for Aluminium, the 13th element in the periodic table of elements.
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