Properties of the Transition Elements

In this chapter, we cover the cf-block elements only. We first discuss some properties of the elements and then focus on the most distinctive feature of their chemistry, the formation of coordination compounds—substances that contain complex ions. 

Concepts Skills to Review Before You Study This Chapter 

Lewis acid-base concepts (Section 18.8) complex-ion formation (Section 19.4) redox behavior and standard electrode potentials (Section 21,3) 

CHAPTER 22 The Transition Elements and Their Coordination Compounds 

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What properties of the transition elements are consistent with their being classified as metals ... 

In the papers referred to above it is pointed out that the mechanical properties of the transition elements and the distances between atoms in metals and intermetallic compounds are well accounted for by these considerations. In the following sections of the present paper a discussion is given of the number of valence electrons by the Brillouin polyhedron method, and it is shown that the calculations for the filled-zone alloys such as the 7-alloys provide further support for the new system of metallic valences. 

Manganese represents the epitome of that characteristic property of the transition element namely the variable oxidation state. The aqueous solution chemistry includes all oxidation states from Mn(II) to Mn(VII), although these are of varying stability. Recently attention has been focused on polynuclear manganese complexes as models for the cluster of four manganese atoms which in conjunction with the donor side of Photosystem(II) is believed involved in plant photosynthetic oxidation of water. The Mn4 aggregate cycles between 6 distinct oxidation levels involving Mn(II) to Mn(IV). 

Let s look at some trends in the properties of the transition elements shown in Table 20.1 and try to understand them in terms of electron configurations. 

Differences in the physical properties of the transition elements, such as melting points and densities, can be established from data books. 

The particular properties of the transition elements are exploited in a remarkable variety of applications. Some metals are used in very large quantities, particularly iron in structural materials, while others are used in only small quantities for specialized applications such as the synthesis of fine chemicals. 

I. The iHoniic and ionic properties of the transition elements underlie their chemical behaviour. The effective nuclear charge experienced by valence shell electrons depends upon shielding and penetration effects. 

The chemical properties of the transition elements do not change so strikingly with change in atomic number as do those of the other elements. In the series potassium, calcium, scandium the normal salts of the elements correspond to the maximuni oxidation numbers given by the positions of the elements in the periodic system, 1 for potas Slum, 2 for calcium, and 3 for scandium the sulfates, for example, of these elements are KoSO, CaSOj, and The fourth element,... 

Discuss the systematic variation of physical and chemical properties of the transition elements through the periodic table (Section 8.1, Problems 1-6). 

Properties of the Transition Elements Other Transition Elements A Variety of Uses Lanthanides and Actinides The Inner Transition Elements MiniLab 8.2 The Ion Gharges of a Transition Element... 

Note added in the proof - It was recently been possible (PS) to extend the Inclined W hypothesis in correlating the properties of the -transition elements and their ions with the L-values of the originating ions. We (PS) have examined a variety of plots, such as, the effective ionic radii (high spin and low spin), ionization energies, electrode potentials, B, C and parameters for the free ions, lattice energies, heats of hydration etc. for the 3 d, 4 d and some 5 d cases. In all cases linearity within each tetrad was preserved. 

The atomic properties of the transition elements contrast in several ways with those of a comparable set of main-group elements (Section 8.4). 

Like their atomic and physical properties, the chemical properties of the transition elements are very different from those of the main-group elements. Let s examine the key properties in the Period 4 transition series. 

Properties of the Transition Elements Electron Configcrations Atomic and Physical Properties Chemical Properties... 

The chemical properties of the transition elements do not change so strikingly with change in atomic number as do those of the other elements. 

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