Alkali group

These elements form two groups, often called the alkali (Group I) and alkaline earth (Group II) metals. Some of the physical properties usually associated with metals—hardness, high m.p. and b.p.—are noticeably lacking in these metals, but they all have a metallic appearance and are good electrical conductors. Table 6.1 gives some of the physical properties. 

Sodium is present in fair abundance in the sun and stars. The D lines of sodium are among the most prominent in the solar spectrum. Sodium is the fourth most abundant element on earth, comprising about 2.6% of the earth s crust it is the most abundant of the alkali group of metals. 

As with other metals of the alkali group, it decomposes in water with the evolution of hydrogen. It catches fire spontaneously on water. Potassium and its salts impart a violet color to flames. 

Rubidium can be liquid at room temperature. It is a soft, silvery-white metallic element of the alkali group and is the second most electropositive and alkaline element. It ignites spontaneously in air and reacts violently in water, setting fire to the liberated hydrogen. As with other alkali metals, it forms amalgams with mercury and it alloys with gold, cesium, sodium, and potassium. It colors a flame yellowish violet. Rubidium metal can be prepared by reducing rubidium chloride with calcium, and by a number of other methods. It must be kept under a dry mineral oil or in a vacuum or inert atmosphere. 

The performance of VASP for alloys and compounds has been illustrated at three examples The calculation of the properties of cobalt dislicide demonstrates that even for a transition-metal compound perfect agreement with all-electron calculations may be achieved at much lower computational effort, and that elastic and dynamic properties may be predicted accurately even for metallic systems with rather long-range interactions. Applications to surface-problems have been described at the example of the. 3C-SiC(100) surface. Surface physics and catalysis will be a. particularly important field for the application of VASP, recent work extends to processes as complex as the adsorption of thiopene molecules on the surface of transition-metal sulfides[55]. Finally, the efficiciency of VASP for studying complex melts has been illustrate for crystalline and molten Zintl-phases of alkali-group V alloys. 

Many liquid alloys, in particular, the alkali-group IV alloys, exhibit (Zintl) anion clustering and show strong effects of compound formation. A typical example of such Zintl systems are sodium-tin alloys. In the solid NaSn crystal the Zintl anions Sn appear [1]. An interesting question is the stability of these anions in the liquid. Furthermore, the electrical conductivity of these alloys shows a strong dependence on composition [2] For the limiting (sodium-rich or tin-rich) cases a metallic (small) conductivity appears, but for the nearly equimolar compositions a semi-metallic behavior - with a considerably smaller conductivity - is observed. 

Carbon dioxide flooding is the most promising enhanced oil-recovery method. To overcome the tendency of CO2 to bypass the smaller pores containing residual oil, one approach is to plug the larger pores by chemical precipitation. Several relatively inexpensive water-soluble salts of the earth alkali group react with CO2 to form a precipitate. 

The importance of alkali group 14, 15, and 16 derivatives cannot be overstated, with a host of far reaching applications, as summarized in several review articles on the subject.1-12 Outstanding coverage on the subject is also provided in Elschenbroich s organometallic text.13... 

On a fifth element belonging to the alkali group, by Professor Bunsen, Chem... 

The hydrated metal hydroxy complex in Eq. (1.10) is a soluble species. However, if the pH is sufficiently high, the metal hydroxide, which is relatively insoluble for most metals (apart from the alkali group metals) will precipitate. The pH value at which hydroxide precipitation occurs can be related to the acidity of the cation and is approximately equal to the pK of the cation, where the pK is minus the logarithm of the equilibrium constant of Eq. (1.10). 

Manufacturing of electrochemicals (other than those covered under alkali group)... 

Compounds of Group I. — There is a general resemblance between the compounds of the elements of the alkali group. The chief distinctive features of the compounds of lithium, rubidium, and caesium have already... 

It was at Winnington, the home of the Alkali Group of ICI, that polythene, Id s major discovery before the Second World War, was taken from laboratory experiments to large-scale production. Several Oxonians played an important role. Firstly, in 1931 Robinson, who was a consultant to Id s Dyestuffs group, suggested that several reactions be tried under very high pressures without catalysts. One reaction in his list was that between ethylene and benzaldehyde. The work he outlined was done at Winnington by... 

It is one of the most reactive and electropositive of the metals. Except for lithium, it is the lightest known metal. It is soft, easily cut with a knife, and is silvery in appearance immediately after a fresh surface is exposed. It rapidly oxidizes in air and must be preserved in a mineral oil, such as kerosene. As with other metals of the alkali group, it decomposes in water with the evolution of hydrogen. It catches fire spontaneously on water. Potassium and its salts impart a violet color to flames. 

Sodium An element that is a member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23. With a valence of 1, it has a strong affinity for oxygen and other nonmetaUic elements. Sodium provides the chief cation of the extracellular body fluids. Its salts are the most widely used in medicine. (From Dorland, 27th ed) Physiologically the sodium ion plays a major role in blood pressure regulation, maintenance of fluid volume, and electrolyte balance. [NIH]... 

The first two columns of the periodic table are known as the alkali (Group 1) and alkaline earth (Group 2) metals. The elements in both groups have very low ionization energies, which means they readily give up one or two electrons to reach a Noble gas electron configuration (e.g., Na+, Mg +j. In their elemental forms, these elements are soft, silver-colored substances. These elements are almost never found in their pure elemental state in nature because they quickly react with air or moisture, sometimes violently. 

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