Electron configurations alkali metals

Lithium chemistry Lithium is an alkali metal, electronic configuration ls 2s forming a... 

Some excited configurations of the lithium atom, involving promotion of only the valence electron, are given in Table 7.4, which also lists the states arising from these configurations. Similar states can easily be derived for other alkali metals. 

In the sodium atom pairs of 3/2 states result from the promotion of the 3s valence electron to any np orbital with n > 2. It is convenient to label the states with this value of n, as n P 1/2 and n f 3/2, the n label being helpful for states that arise when only one electron is promoted and the unpromoted electrons are either in filled orbitals or in an x orbital. The n label can be used, therefore, for hydrogen, the alkali metals, helium and the alkaline earths. In other atoms it is usual to precede the state symbols by the configuration of the electrons in unfilled orbitals, as in the 2p3p state of carbon. 

For hydrogen and the alkali metal atoms in their ground configurations, or excited configurations involving promotion of the valence electron, there is only one electron with an unpaired spin. For this electron = - - or — and the corresponding electron spin part... 

In coating fullerenes with alkali metals, the stability of the cluster seemed to be determined primarily by the electronic configuration. The units C qM and C7oMg, where M is any alkali metal, proved to be exceptionally stable cluster building blocks. Coating a fullerene with more than 7 alkali metal atoms led to an even-odd alternation in the mass spectra, inter-... 

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. 

It is possible to explain these trends in terms of the electron configurations of the corresponding atoms. Consider first the increase in radius observed as we move down the table, let us say among the alkali metals (Group 1). All these elements have a single s electron outside a filled level or filled p sublevel. Electrons in these inner levels are much closer to the nucleus than the outer s electron and hence effectively shield it from the positive charge of the nucleus. To a first approximation, each inner electron cancels the charge of one pro-... 

Give the notation for the valence-shell configuration (including the outermost (/-electrons) of (a) the alkali metals ... 

As in the discussion of hydrogen, in this section we examine the properties of the alkali metals in the context of the periodic table and focus on significant applications of the elements and selected compounds. The valence electron configuration of the alkali metals is s1, where n is the period number. Their physical and chemical properties are dominated by the ease with which the single valence electron can be removed (Table 14.3). 

In addition to having similar electron configurations, some blocks have common chemical characteristics, too. The block of elements on the far left of the illustration, for example, are all metals. The two groups in the block are called the alkali metals (first column) and alkaline earth metals (second column). The alkali metals are remarkably similar soft, silvery, highly reactive metals. The alkaline earth metals form another distinctive group that are much harder that the alkaline metals and have higher melting points. 

Most of the U-series nuclides are metals. Five of them belong to the actinide family corresponding to the filling of the internal orbitals while the orbitals 7s are filled. A sixth, Ra is an alkali earth and shares some chemical properties with other alkali earths, particularly the heavier ones (Sr and Ba), while a seventh, Rn, is a noble gas. The filling of the orbitals prescribes the possible oxidation states of these elements. Their preferred oxidation state is obtained when the electronic configuration is that of the closest rare gas (Rn). 

A The noble gases exhibit the highest ionization energies because, according to the octet rule, they have optimal electron configurations. The ionization energies of the alkali metals are correspondingly low. 

The atomic number of the yet-to-be discovered alkali metal in period 8 is 119. The last portion of its electron configuration after [Rn] (atomic number = 86) should be ... 

When an alkali metal (Group 1A) with atomic configuration, ns reacts with a nonmetal, its outermost s electron is transferred to the nonmetal. The atom becomes an ion with a +1 charge that is isoelectronic with a noble gas. The size of the ion as set by the electron cloud becomes smaller than its parent atom. 

Systematic TRSHG studies on alkali-atom adsorbed metal surfaces by Matsumoto and coworkers provided a deep insight on how coherent motions are created under very different electronic configurations [15, 77, 78]. The results showed that the coherent phonon generation critically depends on the surface and bulk electronic structure of the substrate. 

With Na, the electron configuration of which may also be described as [Ne s1, the third period begins. A similar situation is found for each of the other periods in the Table the number of the period is the principal quantum number of the least tightly bound electron of the first element (an alkali metal) of the period. A few more details of these questions and the characteristics of special points in the Periodic Table are discussed in following paragraphs. The electron configurations of all the elements are given in Chapter 5. 

The block s, on the left of the Table, contains the alkali and alkaline earth metals. Each atom of these metals possesses an inert gas core and one or two electrons in the s orbital of the valence shell, that is, an external electron configuration ns1 or ns2 where n is the value of the principal quantum number, and also the period number in the Periodic Table. Notice however that He, owing to its general chemical inertness and to the behaviour similarity with the other noble gasses is generally placed at the far right of the Table. The p block contains elements corresponding to electron... 

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