Potassium, configuration

Is 2s 2p 3s 3p 3d 4s. If the 3d states were truly core states, then one might expect copper to resemble potassium as its atomic configuration is ls 2s 2p 3s 3p 4s The strong differences between copper and potassium in temis of their chemical properties suggest that the 3d states interact strongly with the valence electrons. This is reflected in the energy band structure of copper (figure Al.3.27). 

The stereochemistry of hydrogen-deuterium exchange at the chiral carbon in 2-phenylbutane shows a similar trend. When potassium t-butoxide is used as the base, the exchange occurs with retention of configuration in r-butanol, but racemization occurs in DMSO. The retention of configuration is visualized as occurring through an ion pair in which a solvent molecule coordinated to the metal ion acts as the proton donor... 

The new /-hydrastine is considered to be /-a-hydrastine and natural hydrastine to be /- -hydrastine, which implies (1) that the latter differs from natural narcotine (/-a-narcotine) in stereochemical configuration (2) that since a-gnoscopine, but not -gnoscopine, can be resolved, the synthesis of natural hydrastine will involve the deracemisation of hydra-stine-b, to /-a-hydrastine, which can be epimerised to natural hydrastine (/- -hydrastine) by boiling with methyl-alcoholic potassium hydroxide. 

Dehydration of (8) with dilute methanolic potassium or sodium hydroxide at reflux is accompanied by inversion of the C-6 methyl group to the 6a-configuration to give (9).i36-i40... 

PerfluoroaUcenes are converted to vicinal diols when no fluonne atom is present at the double bond Configurational isomers of perfluoroalkenes [29] (equations 20 and 21) are oxidized stereospecifically Perfluorbicyclo[4 3 0]non-1(6) ene gives the corresponding 1,6 diol m a 24% yield upon oxidation with potassium permanganate at 18 °C for 1 h [29]... 

An earlier report (126) which assigned the irons configuration to the enamine (175) derived from the cyanamine (176) upon reaction with potassium amide in liquid ammonia has been questioned by Munk and Kim (725). They also have doubts about the structures (177 and 178) proposed for the products obtained by the reduction of acetonitrile with sodium (727). 

The alkali metals form a homogeneous group of extremely reactive elements which illustrate well the similarities and trends to be expected from the periodic classification, as discussed in Chapter 2. Their physical and chemical properties are readily interpreted in terms of their simple electronic configuration, ns, and for this reason they have been extensively studied by the full range of experimental and theoretical techniques. Compounds of sodium and potassium have been known from ancient times and both elements are essential for animal life. They are also major items of trade, commerce and chemical industry. Lithium was first recognized as a separate element at the beginning of the nineteenth eentury but did not assume major industrial importance until about 40 y ago. Rubidium and caesium are of considerable academic interest but so far have few industrial applications. Francium, the elusive element 87, has only fleeting existence in nature due to its very short radioactive half-life, and this delayed its discovery until 1939. 

As shovm above, the attachment of the aromatic ring to the carbon chain bearing the basic nitrogen may be accomplished through an ester or an amide configured in either direction. A simple ether linkage fulfills this function in yet another compound that exhibits local anesthetic activity. Thus, alkylation of the mono potassium salt of hydroquinone with butyl bromide affords the ether (77) alkylation of this with w-C3-chloropropyl)morpholine affords pramoxine (78)... 

Acid resistance This property is best appreciated when the glass structure is understood. Most enamel frits are complex alkali metal borosilicates and can be visualised as a network of Si04 tetrahedra and BO, triangular configurations containing alkali metals such as lithium, sodium and potassium or alkaline earth metals, especially calcium and barium, in the network interstices. 

The structure of KNbF6 consists of potassium ions and isolated NbF6 complex ions that were shown by Bode and Dohren to occur in the lattice in a configuration similar to that of a-CsCl [165]. The complex anion Nb(Ta)F6 has a configuration of a distorted bi-pyramid (four fluorine atoms are shifted in pairs from their positions in the basic plane, towards the vertexes). The structure of KNb(Ta)F6 compounds and of the Nb(Ta)F6 polyhedron are shown in Fig. 26. Nb/Ta-F distances are equal to 2.13 and 2.15 A, respectively, and F-F distances are 2.61, 3.03, 3.22 and 3.55 A. Each potassium atom is surrounded by 12 fluorine atoms that are at unequal distances from each other 8 of them are 2.50 A apart and four others are 2.94 A apart. 

Turn back to Figure 15-11, the energy level diagram of a many-electron atom, and consider the occupied orbitals of the element potassium. With 19 electrons placed, two at a time, in the orbitals of lowest energy, the electron configuration is... 

Potassium, 93 atomic radius, 399 atomic volume, 410 chemistry, 95 electron configuration, 271 heat of vaporization, 305 ionization energy, 268 properties, 94... 

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