Representative elements electron configurations

The table shows the electronic configuration in spectroscopic and orbital box notation for the elements from scandium to zinc. [Ar] represents the electronic configuration of argon, which is Is 2s 2p 3s 3p . It is okay to use this shorthand here instead of writing out the full electron shells up to 3p. However, in the exam you should write out the spectroscopic notation for each element in full. 

This notation can be used to represent the electronic configuration of a molecule that contains more than two different elements, but this can easily become confusing. Often the electrons that originate from the third element would be represented by a small square, or such like. If that element occurred only in an isolated part of the molecule, then it might be represented by either a dot or a cross, whichever was the more convenient. 

The symbol [Ne] represents the electron configuration of the ten electrons of neon, ls 2s 2p. Writing the electron configuration in this manner helps focus attention on the outermost electrons of the atom. The outer electrons are the ones largely responsible for the chemical behavior of an element. 

Assume that the third-period element phosphorus forms a diatomic molecule, P2, in an analogous way as nitrogen does to form N2. (a) Write the electronic configuration for P2. Use [Ne2] to represent the electron configuration for the first two periods, (b) Calculate its bond order, (c) What are its magnetic properties (diamagnetic or paramagnetic) ... 

The electronic configurations of some of the elements after argon are shown in Table 3.6. In this table part of the electronic configuration of each element is represented by [Ar]. This noble gas core represents the electronic configuration of argon ls 2s 2p 3s 3p . This method is a shorthand way of writing electronic structures of atoms with many electrons. However, in an exam you should be prepared to write out the full electronic configuration. 

Bohr diagrams shewing the electronic configurations for the first ten elements, along with representative bond formation,... 

This idea is readily extended to simple molecules of compounds formed by nonmetal atoms. An example is the HF molecule. You will recall that a fluorine atom has the electron configuration ls22s22p5. ft has seven electrons in its outermost principal energy level (n = 2). These are referred to as valence electrons, in contrast to the core electrons filling the principal level, n = 1. If the valence electrons are shown as dots around the symbol of the element, the fluorine atom can be represented as... 

The potential surfaces Eg, Hn, and H22 of the HF molecule are described in Fig. 1.6. These potential surfaces provide an instructive example for further considerations of our semiempirical strategy (Ref. 5). That is, we would like to exploit the fact that Hn and H22 represent the energies of electronic configurations that have clear physical meanings (which can be easily described by empirical functions), to obtain an analytical expression for the off-diagonal matrix element H12. To accomplish this task we represent Hn, H22, and Eg by the analytical functions... 

The noble gases, located at the end of each period, have electron configurations of the type ns2np6, where n represents the number of the outermost shell. Also, n is the number of the period in the periodic table in which the element is found. 

Transition metals tend to have higher melting points than representative metals. Because they are metals, transition elements have relatively low ionization energies. Ions of transition metals often are colored in aqueous solution. Because they are metals and thus readily form cations, they have negative standard reduction potentials. Their compounds often have unpaired electrons because of the diversity of -electron configurations, and thus, they often are paramagnetic. Consequently, the correct answers are (c) and (e). 

In some cases, it would be convenient to condense the electron configuration. In this condensed form, the electronic configuration of the previous noble gas forms a core represented by the atomic symbol of the element enclosed in brackets (i.e., [He] or [Ne]). The electrons added since the noble gas, follow the noble gas core. For example, cobalt can be represented as an argon core plus the 4s and 3d electrons. Thus, ls22s22p63s23p64s23d7 becomes [Ar]4s23d7. 

The condensed electron configuration for a nitrogen atom, for example, is [He]2s 2p. The notation [He] is used to represent Is. For a sodium atom [Z = 11), the condensed electron configuration is [Ne]3s. Here, [Ne] represents, ls 2s 2p . Be aware that condensed electron configurations are simply convenient short forms. Thus, [Ne]3s does not mean that a sodium atom is the same as a neon atom plus one electron. Sodium and neon are different elements because the nuclei of their atoms are completely different. 

The p block includes elements of groups 13 (IIIA) through 18 (VIIIA). Electron configurations of the p block atoms take the general form ns np°, where a represents a value ranging from 1 to 6. Because the three p orbitals can hold a maximum of six electrons, the p block elements span six groups. 

Considering the influence of electronic configurations on crystal structures it may be asked, whether certain structure t5rpes are restricted to fluorine compounds of the transition elements. Apart from the structure types distorted by the Jahn-Teller effect such a limitation is not obvious at all. On the contrary quite a number of structure prototypes are represented by compounds of the main group elements. Bonding thus must be similar in both, main group and transition element fluorides, at least as for the factors that influence crystal structmes. 

Group 3 of the Periodic Table consists of the elements scandium, yttrium and either lanthanum or lutetium, depending upon the preferred arrangement of the Table. Group 3 elements have the outer electronic configuration ns2 p, and invariably their solution chemistry is that of the + 3 state. In this text, treatment of both La and Lu is carried out in Chapter 8, which deals with the f-block elements. Lanthanum and lutetium represent the first and last members of the lanthanide series. 

We might, just accept it as a brute fact about the world that the series of elements was discrete. But if there were a finite number of properties, combinations of which generate the physical possibilities represented by the periodic table, then variation would necessarily be discrete rather than continuous. We can believe in the existence of these fundamental entities and properties without subscribing to any particular account of them (e.g. an account in terms of electronic configuration), such accounts at least show us the way in which chemical properties could be determined by more fundamental ones. The point is that, given the principle of recombination, unless those more fundamental properties exist, unactualized elements would not be physical possibilities (14). 

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