Characteristic oxidation number

The outermost electrons, often called the valence electrons, are primarily responsible for the chemical properties of the elements. It follows that the elements in a specific group will show similar characteristic oxidation numbers (charges, also called valences) and display a trend in characteristics. Even though electron configurations were not known when the earliest periodic tables were formulated, the elements were placed by similarity of characteristics. 

Table 4.3 The electron configurations, characteristic oxidation number and...

The idea of a characteristic oxidation number based on the electron configuration of an element suggests that the elements only form a single characteristic oxidation number, as in Figure 4.1. 

When the characteristic element is partially or wholly present in a lower oxidation state than corresponds to its Periodic Group number, oxidation numbers are used for example, [O2HP—O—P03H] , dihydrogendiphosphate(III,V)(2—). 

The very slight differences that do exist among these elements are due to small changes in size brought about by increase of nuclear charge. The separation of the lanthanide elements from each other is based upon clever exploitation of these slight differences in properties. Table 23-1 shows a comparison of some of the properties of the various lanthanide elements. As can be seen, +3 is the common oxidation number and is most characteristic of the chemistry of these elements. Another thing to note is the steady decrease in... 

The valence electron configuration of the atoms of the Group 2 elements is ns1. The second ionization energy is low enough to be recovered from the lattice enthalpy (Fig. 14.18). Flence, the Group 2 elements occur with an oxidation number of +2, as the cation M2+, in all their compounds. Apart from a tendency toward nonmetallic character in beryllium, the elements have all the chemical characteristics of metals, such as forming basic oxides and hydroxides. 

Variable oxidation state - One obvious feature of transition-metal chemistry is the occurrence of a number of characteristic oxidation states for a particular metal... 

Contents Formal Oxidation Numbers. Configurations in Atomic Spectroscopy. Characteristics of Transition Group Ions. Internal Transitions in Partly Filled Shells. Inter-Shell Transitions. Electron Transfer Spectra and Collectively Oxidized Ligands. Oxidation States in Metals and Black Semi-Conductors. Closed-Shell Systems, Hydrides and Back-Bonding. Homopolar Bonds and Catenation. Quanticule Oxidation States. Taxological Quantum Chemistry. 

Indicate the position of iron, cobalt, and nickel in Mendeleev s periodic table of the elements, the electron configurations and sizes of their atoms, and their oxidation states. Explain the observed law of the change in the characteristic oxidation states in the series iron-cobalt-nickel. Why do the elements of the iron family fail to exhibit the highest oxidation state corresponding to the number of the group in the periodic table which they belong to ... 

The nature of the binary hydride is related to the characteristics of the parent element (Fig. 14.8). Strongly electropositive metallic elements form ionic compounds with hydrogen in which the latter is present as a hydride ion, H, and has oxidation number —1. These ionic compounds are called saline hydrides (or saltlike hydrides ). They are formed by all members of the s block with the exception of beryllium and are made by heating the metal in hydrogen ... 

T50I(NPG)/PMDA was of particular interest because of its adhesive characteristics, oxidative stability, and polymer cost. Table III shows the improvement in adhesion obtained when various substrates were coated with blends containing this polyester (acid number 39). As indicated in the table, the ease of obtaining adhesion on the different substrates decreased approximately in the following order brass > steel > copper > chrome-coated steel > aluminum > nylon 66 > poly (ethylene terephthalate). In spite of the wide differences in structure and polarity of the various polymers, the carboxylated polyester significantly improved the adhesion of the coatings. 

The writer4,179 analyzed the hydration energy differences derived from Eq. (31) for aqua ions, where E° is known for the process increasing the oxidation number from (z — 1) to z. It turns out that each transition group has a characteristic constant K such that... 

The columns of Table 17.1 contain characteristic substructures ordered by common average carbon oxidation numbers. Also, the average carbon oxidation number increases in going from left to right in this table. Accordingly, reactions are oxidations if they convert a substructure of one column into a substructure of a column that is further to the right. The opposite is true for reductions. 

The oxidation number of manganese in manganate is + 6. MnOj- ions exhibit a characteristic green colour. When permanganate is heated with alkalis, such a reduction takes place and oxygen is formed ... 

The chemistry of reduced Nb and Ta hahdes is rich in clusters with various structures. The metal atoms assemble with metal metal distances close to those in the metal into triangular and tetranuclear clusters but the dominant structural motif is that of the octahedral M6X12 and NbeIg types. Binary, ternary, and quaternary compounds aU crystallize in that type. The Me clusters are characteristic of the chemistry of the lower oxidation states of Nb and Ta, although not restricted to them. These electron-deficient clusters are based on metal ions with average oxidation numbers between III and I. 

In each of these molecules the sulfur atom has one unshared pair of electrons this is characteristic of atoms with oxidation number two less than the maximum. 

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