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Scandium compounds are compounds containing the element scandium. The chemistry of scandium is almost completely dominated by the trivalent ion, Sc 3+ , due to its electron configuration , [Ar] 3d 1 4s 2 .
As is observed for most elements, a diatomic scandium hydride has been observed spectroscopically at high temperatures in the gas phase. [5] Scandium borides and carbides are non-stoichiometric, as is typical for neighboring elements. [41] Lower oxidation states (+2, +1, 0) have also been observed in organoscandium compounds. [42] [4] [43] [44]
The elements, after purification from other rare-earth metals, are isolated as oxides; the oxides are converted to fluorides during reactions with hydrofluoric acid. [79] The resulting fluorides are reduced with alkaline earth metals or alloys of the metals; metallic calcium is used most frequently. [79] For example: Sc 2 O 3 + 3 HF → 2 ScF 3 ...
Here [Ne] refers to the core electrons which are the same as for the element neon (Ne), the last noble gas before phosphorus in the periodic table. The valence electrons (here 3s 2 3p 3) are written explicitly for all atoms. Electron configurations of elements beyond hassium (element 108) have never been measured; predictions are used below.
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 ...
Oxygen (1s 2 2s 2 2p 4), fluorine (1s 2 2s 2 2p 5), and neon (1s 2 2s 2 2p 6) then complete the already singly filled 2p orbitals; the last of these fills the second shell completely. [ 39 ] [ 58 ] Starting from element 11, sodium , the second shell is full, making the second shell a core shell for this and all heavier elements.
The alkali metals form many intermetallic compounds with each other and the elements from groups 2 to 13 in the periodic table of varying stoichiometries, [10]: 81 such as the sodium amalgams with mercury, including Na 5 Hg 8 and Na 3 Hg. [106]
Lithium has two electrons in the 1s-subshell and one in the (higher-energy) 2s-subshell, so its configuration is written 1s 2 2s 1 (pronounced "one-s-two, two-s-one"). Phosphorus (atomic number 15) is as follows: 1s 2 2s 2 2p 6 3s 2 3p 3. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used.