Transition elements scandium

The third period terminates at argon (Z — 18) with the configuration (2, 8, 8), but here a new phenomenon occurs although the M shell is not yet fully occupied, the further electrons in potassium (Z = 19) and calcium (Z = 20) enter the N shell. Only after two electrons have taken their place in this shell is the development of the M shell resumed to give the transition elements scandium, titanium, etc. it is finally com-... 

In the first series of transition elements (scandium to zinc), the elements have two electrons in the s orbital of their fourth shell and d orbitals in their third shell that fill across the row (there can be 10 electrons in d orbitals). 

General Properties 23-2 Principles of Extractive Metallurgy 23-3 Metallurgy of Iron and Steel 23-4 First-Row Transition Elements Scandium to Manganese 23-5 The Iron Triad Iron, Cobalt, and Nickel... 

First-Row Transition Elements Scandium to Manganese—Oxidation-reduction reactions are commonly encountered with transition metal compounds of Sc, Ti, V, Cr, and Mn. Two common types of oxidizing agents are the dichromates and permanganates. In aqueous solution, dichromate ion is in equilibrium with chromate ion. 

Compared to later elements in their respective transition series, scandium, yttrium and lanthanum have rather poorly developed coordination chemistries and form weaker coordinate bonds, lanthanum generally being even less inclined to form strong coordinate bonds than scandium. This is reflected in the stability constants of a number of relevant 1 1 metal-edta complexes ... 

There is some disagreement among chemists as to just which elements should be called transition elements. For our purposes, it will be convenient to include all the elements in the columns of the periodic table headed by scandium through zinc. 

In fact this explanation for the configuration of the scandium atom and most other first transition elements is inconsistent. If the 3d... 

The transition elements comprise groups 3 to 12 and are found in the central region of the standard periodic table, an example of which is reproduced on the endpaper. This group is further subdivided into those of the first row (the elements scandium to zinc), the second row (the elements yttrium to cadmium) and the third row (the elements lanthanum to mercury). The term transition arises from the elements supposed transitional positions between the metallic elements of groups 1 and 2 and the predominantly non-metallic elements of groups 13 to 18. Nevertheless, the transition elements are also, and interchangeably, known as the transition metals in view of their typical metallic properties. 

All the transition elements have large atomic numbers, the smallest (scandium) having 21 protons. All of them have at least four energy shells holding their electrons. Scientists do not know exactly why, but the transition element atoms often put electrons into a new, outer energy shell when some inner shells are not quite full. All the transition elements have one or two electrons in their outer shells, but from element to element each new electron is added to a shell deep inside the electron cloud. 

The strangest section of the periodic chart comes in the first transition subgroup. Under scandium and yttrium (marked with stars on the periodic chart) fall two long horizontal lists of elements so much alike that they are squeezed into two squares of the chart. Elements with the atomic numbers 57-71 are called the lanthanides. The actinides are elements with the atomic numbers 89-103, and they are all radioactive. These transition elements are as follows ... 

The 3rd group of the Periodic Table (the 1st column within the block of the transition elements) contains the metals scandium, yttrium, lanthanum, and actinium. Lanthanum (atomic number 57) may be considered the earliest member of the family of metals, called lanthanides (general symbol Ln), forming, inside the principal transition series, an inner transition series (up to atomic number 71). Scandium and yttrium together with the lanthanides are also called rare earth metals (general symbol R). 

Scandium is the first element in the fourth period of the transition elements, which means that the number of protons in their nuclei increases across the period. As with all the transition elements, electrons in scandium are added to an incomplete inner shell rather than to the outer valence shell as with most other elements. This characteristic of using electrons in an inner shell results in the number of valence electrons being similar for these transition elements although the transition elements may have different oxidation states. This is also why all the transition elements exhibit similar chemical activity. 

This chapter consists of a description of the ions formed in aqueous solutions by the transition elements - the d-block elements - and a discussion of the variations of their redox properties across the Periodic Table from Group 3 to Group 12. There is particular emphasis on the first transition series from scandium to zinc in the fourth period, with summaries of the solution chemistry of the second (Y to Cd) and third (Lu to Hg) series. The d-block ions in solution are those restricted solely to aqua complexes of cations, e.g. [Fe(H20)f,]" +, and the various oxocalions and oxoanions formed, e.g. V02+ and MnCXj". Oxidation states that are not well characterized are omitted or referred to as such. 

There are other subtleties in electron configurations for the transition elements illustrated in Table S.3. For all the neutral atoms from scandium to zinc, the 4s orbitals are the most easily ionized, and are removed first in... 

Transition elements Some elements that lie in rows 4-7 of the periodic table, comprising scandium through zinc, yttrium through cadmium, and lanthanum through mercury. 

Crystal field theory is one of several chemical bonding models and one that is applicable solely to the transition metal and lanthanide elements. The theory, which utilizes thermodynamic data obtained from absorption bands in the visible and near-infrared regions of the electromagnetic spectrum, has met with widespread applications and successful interpretations of diverse physical and chemical properties of elements of the first transition series. These elements comprise scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel and copper. The position of the first transition series in the periodic table is shown in fig. 1.1. Transition elements constitute almost forty weight per cent, or eighteen atom per cent, of the Earth (Appendix 1) and occur in most minerals in the Crust, Mantle and Core. As a result, there are many aspects of transition metal geochemistry that are amenable to interpretation by crystal field theory. 

Transition elements. Elements of the first transition series are characterized by having incompletely filled 3d orbitals in one or more of their common oxidation states. The series includes scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel and copper, which have electronic configurations of the form (ls)2(2s)2(2p)6(3s)2(3p)6(3[Pg.41]

The elements after the rare gas argon all have an inner group of electrons called the argon core and, in addition, outer electrons that determine the chemical properties of the elements. After both the 4s and 3d subsheiis are filled at zinc, the next electron goes into the 4p subshell. The elements from scandium to nickel having incomplete inner (3d) subshells comprise the first row of transition elements. The "discontinuities in the order of... 

We have already discussed the microwave/optical double resonance spectrum of the MoN molecule in its X4 groundstate. We now deal with studies of YF, YOand YS, yttrium being the first member of the 4d transition elements analogous to scandium in the 3d series. 

Two notable points from the aforegoing discussion are as follows. (1) By far the majority of the known monohalogenoalkyl compounds are of the group VTII transition elements there are very few early transition metal halogenoalkyl compounds known. (2) Very few monofluoroalkyl metal complexes have been prepared. The lack of early transition metal halogenoalkyl compounds may be in part due to the high electropositivity of these metals, which facilitates a- and / -elimination reactions. Related hydride elimination reactions almost certainly occur more easily for early transition metal alkyl compounds than for later transition metal compounds. In this regard it is particularly noteworthy that one of the only early transition metal haloalkyl compounds mentioned is the fluoroethyl scandium com-... 

The ground state configuration of lanthanides, 4/" l5d 6s2 or 4/"6s2 does not determine the chemical behaviour of these elements. In forming Ln3+ ions, an / electron is removed. Lanthanides differ from transition elements in that 4/ orbitals are shielded and are not available for reactions. Thus lanthanides resemble more closely alkaline earths and the scandium group than transition elements in their chemistry. 

The analytical chemistry of the transition elements see Transition Metals), that is, those with partly filled shells of d (see (f Configuration) or f electrons see f-Block Metals), should include that of the first transition period (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) and that of the second transition series (Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, and Ag). The third transition series embraces Hf, Ta, W, Re, Os, Ir, Pt, and An, and although it formally begins with lanthanum, for historical reasons this element is usually included with the lanthanoids (rare-earth elements) see Scandium, Yttrium the Lanthanides Inorganic Coordination Chemistry Rare Earth Elements). The actinoid elements see Actinides Inorganic Coordination Chemistry) are all radioactive see Radioactive Decay) and those with atomic number see Atomic Number) greater than uranium (Z = 92) are artificial the analytical chemistry of these elements is too specialized to consider here. 

IV. Chalcogenocyanate Complexes of the Transition Elements A. Scandium, Yttrium, Lanthanum, and the Lanthanides i. Cyanates... 

The next element, scandium, begins a series of ten elements (scandium through zinc) called the transition metals, whose configurations are obtained by adding electrons to the five 3d orbitals. The configuration of scandium is... 

In this chapter we will concentrate on the first-row transition metals (scandium through zinc) because they are representative of the other transition series and because they have great practical significance. Some important properties of these elements are summarized in Table 20.2 and are discussed below. 

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