Alkali metals Group chemical properties

The members of Group 1 are called the alkali metals. The chemical properties of these elements are unique and strikingly similar from one to another. Nevertheless, there are differences, and the subtlety of some of these differences is the basis of the most subtle property of matter consciousness. Our thinking, which relies on the transmission of signals along neurons, is achieved by the concerted action of sodium and potassium ions and their carefully regulated migration across membranes. So, even to learn about sodium and potassium, we have to make use of them in our brains. 

Sodium is the alkali metal, the chemical properties of which are best established in the molten state. Lithium chemistry has been improved during the last decade due to the interest of the fusion reactor technology. Nevertheless, several chemical properties are still unknown. Potassium and the heavy alkali metals still require research work concerning the solutions of their compounds with non-metals, as well as on the solu-bihty of metallic elements. The solubility of transition elements may range at the same level as in sodium. The degree of solubility of the elements of the fourth and fifth groups and the formation of intermetallic compounds with them are not well known. Further research may detect some new aspects, which may help to improve the application of liquid alkali metals in modem technology and chemistry. 

A column of the periodic table is called a family. Some families have special names. Group IA elements are called alkali metals, group IIA elements are called alkaline earth metals, group VIIA elements are called halogens, and group VIIIA elements are called the noble gases. The group B elements are called transition elements. Elements with atomic numbers from 58 to 71 are called lanthanides, and elements with atomic numbers from 90 to 103 are called actinides. Families have similar chemical and physical properties. For example, the alkali metals are soft metals at room temperature they are shiny, conduct... 

Rubidium [7440-17-7] Rb, is an alkali metal, ie, ia Group 1 (lA) of the Periodic Table. Its chemical and physical properties generally He between those of potassium (qv) and cesium (see Cesiumand cesium compounds Potassium compounds). Rubidium is the sixteenth most prevalent element ia the earth s cmst (1). Despite its abundance, it is usually widely dispersed and not found as a principal constituent ia any mineral. Rather it is usually associated with cesium. Most mbidium is obtained from lepidoHte [1317-64-2] an ore containing 2—4% mbidium oxide [18088-11-4]. LepidoHte is found ia Zimbabwe and at Bernic Lake, Canada. 

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. 

The Group 1 elements are soft, low-melting metals which crystallize with bee lattices. All are silvery-white except caesium which is golden yellow "- in fact, caesium is one of only three metallic elements which are intensely coloured, the other two being copper and gold (see also pp. 112, 1177, 1232). Lithium is harder than sodium but softer than lead. Atomic properties are summarized in Table 4.1 and general physical properties are in Table 4.2. Further physical properties of the alkali metals, together with a review of the chemical properties and industrial applications of the metals in the molten state are in ref. 11. 

Beryllium, at the head of Group 2, resembles its diagonal neighbor aluminum in its chemical properties. It is the least metallic element of the group, and many of its compounds have properties commonly attributed to covalent bonding. Beryllium is amphoteric and reacts with both acids and alkalis. Like aluminum, beryllium reacts with water in the presence of sodium hydroxide the products are the beryl-late ion, Be(OH)42, and hydrogen ... 

The elements in the second column of the table (Group 2) are the alkaline earth metals. These resemble the alkali metals in their appearance, but they have different chemical properties. For example, each of these metals... 

The placement of an unknown element with an atomic number of 87 in group 1, period 7 of the periodic table was one of Dimitri Mendeleevs ideas based on the chemical properties and physical characteristics of the other alkali metals. In the late nineteenth century, Mendeleev named this unknown element eka-cesium and predicted its properties based on what was known of cesium s placement on the periodic table. This led to worldwide searches for element number 87, which were not all successful but which did result in proposed names for eka-cesium (moldavium, virginium, russium). 

The alkali metals of group 1 in the periodic table have chemical properties which indicate that one electron is easily removed. Their optical spectra can be interpreted in a similar way, by the assumption that just one electron can be easily excited between different orbitals. These atoms therefore provide a good example of the use of orbital energies. 

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