Transition metals forming only one ion

Sometimes transition metals form only one ion, such as silver, which forms Ag zinc, which forms Zn and cadmium, which forms Cd. In these cases, chemists do not use a Roman numeral, although it is not "wrong" to do so. 

Certain transition metals form only one ion. Common examples are zinc (forms only Zn " ") and silver (forms only Ag ). For these cases the Roman numeral is omitted from the name. 

Some transition metals form only one type of ion silver forms only Ag ions zinc forms only Zn " ions... 

Note that the use of a Roman numeral in a systematic name is required only in cases in which more than one ionic compound forms between a given pair of elements. This case most commonly occurs for compounds containing transition metals, which often form more than one cation. Elements that form only one cation do not need to be identified by a Roman numeral. Common metals that do not require Roman numerals are the Group 1A elements, which form only 1+ ions the Group 2A elements, which form only 2+ ions and aluminum, which forms only Al3+. Common transition metals that do not require a Roman numeral (because they form only one ion) are zinc (Zn2+) and silver (Ag+). 

For an ionic compound, you must next decide whether the metal forms only one type of ion or more than one type of ion. Group lA (alkali) mefals. Group 2A (alkaline earth) metals, and aluminum will always form only one type of ion (Figure 4.14). Most of the transition metals will form more fhan one type of ion. Once you have identified the type of ionic compound, name if according to fhe scheme in fhe chart. If the ionic compound contains a polyatomic ion—something you must learn to recognize by familiarity—insert the name of the polyatomic ion in place of the metal (positive polyatomic ion) or the nonmetal (negative polyatomic ion). 

Figure 6.2 shows some ions and their location on the periodic table. The transition elements form more than one positive ion except for zinc (Zn ), cadmium (Cd ), and silver (Ag ), which form only one ion. Thus, no Roman numerals are used with zinc, cadmium, and silver when naming their cations. Metals in Groups 4A (14) and 5A (15) also form more than one positive ion. For example, lead and tin in Group 4A (14) form cations with charges of 2-1- and 4-I-, and bismuth in Group 5A (15) forms cations with charges of 3+ and 5-I-. 

Formation of a positive ion by removal of an electron reduces the overall electron repulsion and lowers the energy of the d orbitals more than that of the s orbitals, as shown in Figure 2-12(b). As a result, the remaining electrons occupy the d orbitals and we can use the shorthand notion that the electrons with highest n (in this case, those in the i orbitals) are always removed first in the formation of ions from the transition elements. This effect is even stronger for 2-t- ions. Transition metal ions have no s electrons, but only d electrons in their outer levels. The shorthand version of this phenomenon is the statement that the 4 electrons are the first ones removed when a first-row transition metal forms an ion. 

Note that mercury(l) ions always occur bound together to form Flg2 ions. Although these are transition metals, they form only one type of ion, and a Roman numeral is not used. 

When two generalized solid oxides, AO and B2O3, react to the spinel AB2O4, the atoms move from the solid reactant lattices to the sites of the solid product. The ions A and B can be any main group or transition metal ions. As a specific example these are here taken to be CoO and Fe203, which form only one compound, cobalt ferrite (CoFe204). The marker wires end up somewhere in the spinel area or on the boundary of this phase, depending on how fast the ions of the two reactants are able to diffuse. Some conceivable diffusion mechanisms are in their pure form ... 

Electron configurations of the r/-transition metal atoms include the s electrons in the outermost occupied shell and the d electrons one energy level lower (e.g., 3r/4r for the first transition series in Period 4). The outer s electrons lie outside the d electrons and are always the first ones lost when transition metals form simple ions. In the first transition series, scandium and zinc each form only one type of cation. Scandium loses its two 4r electrons and its only 3d electron to form Sc ". Zinc loses its two 4r electrons to form Zn. ... 

Compounds containing a metal and a nonmetal are ionic. If the metal is a transition metal, it will likely form more than one type of ion (see exceptions in Tables 5.3 and 5.4). If the metal is not a transition metal, it will likely form only one type of ion (see exceptions in Tables 5.3 and 5.4). Compounds composed of nonmetals are molecular. 

These rod-shaped ligands share a sterically efficient terminal N-donor and their divalent Co chemistry is well established. They will be discussed here only with selected examples. [Co (NCMe)6](TFPB)2 (TFPB- = tetrakis(3,5-bis(trifhioromethyl)phenyl)borate)) has been synthesized and characterized in the solid state along with a number of other divalent transition metal analogs.357 As a result of the extremely poor coordinating ability of the anion and facile loss of MeCN ligands from the cation, the salt is an excellent source of naked Co2+ ions. Thermolysis up to 100 °C leads to the loss of one MeCN and formation of a r -bound nitrile, whereas above 130 °C decomposition occurs with loss of MeCN and abstraction of fluoride from the anion to form CoF2. 

Molecular hydrogen is rather unreactive at ambient conditions, but many transition and lanthanide metal ions are able to bind and therefore activate H2, which results in transformation into H (hydride) 11 (hydrogen radical) or H+ (proton), and subsequent transfer of these forms of hydrogen to the substrate.7,8 In this context, not only metal hydride but also dihydrogen complexes of transition metal ions, play a key role,9 10 especially since the first structural characterization of one of these species in 1984 by Kubas.11... 

The primary, secondary, and tertiary aliphatic amines do not form simple addition complex ions with bare transition metal ions. Only Ag+ reacts with MeNH2 to form a simple addition product [AgMeNH2]+ (107). The Pb+ ion also forms addition products, [PbMeNH2]+ and [Pb(MeNH2)2]+, with methylamine (143). Other bare transition metal ions (144) react with amines via removal of one hydrogen to form the metal hydride and the amine cation with one hydrogen removed [RR N]+. 

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