Outer electronic configuration

Loss of one electron gives the noble gas configuration the very large difference between the first and second ionisation energies implies that an outer electronic configuration of a noble gas is indeed very stable. 

In this oxidation state the outer electronic configuration is 3d . so the compounds are necessarily paramagnetic (p. 229) and are coloured. 

With the outer electronic configuration 3d 4s vanadium can attain an oxidation state of -I- 5, but it shows all oxidation states between -I- 5 and -I- 2 in aqueous solution (cf titanium). 

In the older form of the periodic table, chromium was placed in Group VI, and there are some similarities to the chemistry of this group (Chapter 10). The outer electron configuration, 3d 4s. indicates the stability of the half-filled d level. 3d 4s being more stable than the expected 3d 4s for the free atom. Like vanadium and titanium, chromium can lose all its outer electrons, giving chromium)VI) however, the latter is strongly oxidising and is... 

Copper differs in its chemistry from the earlier members of the first transition series. The outer electronic configuration contains a completely-filled set of d-orbitals and. as expected, copper forms compounds where it has the oxidation state -)-l. losing the outer (4s) electron and retaining all the 3d electrons. However, like the transition metals preceding it, it also shows the oxidation state +2 oxidation states other than -l-l and - -2 are unimportant. 

Silver belongs to Group II (IB) of the Periodic Table. The metal has a outer electronic configuration. Silver has been shown to have three... 

Tellurium [13494-80-9] Te, at no. 52, at wt 127.61, is a member of the sixth main group. Group 16 (VIA) of the Periodic Table, located between selenium and polonium. Tellurium is in the fifth row of the Table, between antimony and iodine, and has an outer electron configuration of The four inner... 

Outer electron configuration 2s22p3 3s23p3 2s22p4 Ss p 2s22p5 Ss p5 4s24p5 5s25p5... 

ELEMENT z OUTER ELECTRON CONFIGURATION OXIDATION E° states M — - M+3 + 3e +3 ION RADIUS... 

Most tin(II) compounds display structures with a trigonal pyramidal coordination. This is of course to be expected as the tin atom is in the first place electrophilic in order to complete its outer electron configuration (cf. Chapter 5 and 6). To illustrate the resemblance of this geometry between ionic and molecular compounds, the structure of NH4SnF3 (5) 31) is compared with that of the cage compound (Me3CN)3(Me3A10)Sn4 (6) 32). The coordination sphere of the tin atom is the same in 5 and 6 (for the complete structure of 6 see Sect. 6.5) ... 

The lanthanides have electrons in partly filled 4/orbitals. Many lanthanides show colors due to electron transitions involving the 4/orbitals. However, there is a considerable difference between the lanthanides and the 3d transition-metal ions. The 4/ electrons in the lanthanides are well shielded beneath an outer electron configuration, (5.v2 5p6 6s2) and are little influenced by the crystal surroundings. Hence the important optical and magnetic properties attributed to the 4/ electrons on any particular lanthanide ion are rather unvarying and do not depend significantly upon the host structure. Moreover, the energy levels are sharper than those of transition-metal ions and the spectra resemble those of free ions. 

Elements in a group have similar chemical properties because they have similar outer electron configurations. That is, they have the same number of valence electrons. This observation gives rise to three patterns that you can deduce from the periodic table. 

One of the simplest descriptions of the crystalline field occurs for the d outer electronic configuration (i.e., for a single d valence electron). This means that //ee = 0 and, consequently, there is no distinction between intermediate and strong crystalline fields. 

The rare earth (RE) ions most commonly used for applications as phosphors, lasers, and amplifiers are the so-called lanthanide ions. Lanthanide ions are formed by ionization of a nnmber of atoms located in periodic table after lanthanum from the cerium atom (atomic number 58), which has an onter electronic configuration 5s 5p 5d 4f 6s, to the ytterbium atom (atomic number 70), with an outer electronic configuration 5s 5p 4f " 6s. These atoms are nsnally incorporated in crystals as divalent or trivalent cations. In trivalent ions 5d, 6s, and some 4f electrons are removed and so (RE) + ions deal with transitions between electronic energy sublevels of the 4f" electroiuc configuration. Divalent lanthanide ions contain one more f electron (for instance, the Eu + ion has the same electronic configuration as the Gd + ion, the next element in the periodic table) but, at variance with trivalent ions, they tand use to show f d interconfigurational optical transitions. This aspect leads to quite different spectroscopic properties between divalent and trivalent ions, and so we will discuss them separately. 

Trivalent lanthanide ions have an outer electronic configuration 5s 5p 4f", where n varies from 1 (Ce +) to 13 (Yb +) and indicates the number of electrons in the unfilled 4f shell. The 4f" electrons are, in fact, the valence electrons that are responsible for the optical transitions. 

Divalent rare earth ions also have an outer electronic configuration of 4f"( including one more electron than for the equivalent trivalent rare earth). However, unlike that of (RE) + ions, the 4f " 5d excited configuration of divalent rare earth ions is not far from the 4f" fundamental configuration. As a result, 4f" 4f " 5d transitions can possibly occur in the optical range for divalent rare earth ions. They lead to intense (parity-allowed transitions) and broad absorption and emission bands. 

The 4f outer electronic configuration of Sm + ion leads to states with half-odd integer values of J (see Figure 6.1), due to the half-odd integer values for the total spin S. In these cases, there are some peculiarities in the rotations of... 

Chapter 6 is devoted to discussing the main optical properties of transition metal ions (3d" outer electronic configuration), trivalent rare earth ions (4f 5s 5p outer electronic configuration), and color centers, based on the concepts introduced in Chapter 5. These are the usual centers in solid state lasers and in various phosphors. In addition, these centers are very interesting from a didactic viewpoint. We introduce the Tanabe-Sugano and Dieke diagrams and their application to the interpretation of the main spectral features of transition metal ion and trivalent rare earth ion spectra, respectively. Color centers are also introduced in this chapter, special attention being devoted to the spectra of the simplest F centers in alkali halides. 

The Periodic Table can be subdivided into four blocks (s, p, d and f)- These blocks correspond to the outer electronic configurations of the elements within these blocks. 

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