Coinage metals elements

Ruthenium and osmium are generally found in the metallic state along with the other platinum metals and the coinage metals. The major source of the platinum metals are the nickel-copper sulfide ores found in South Africa and Sudbury (Canada), and in the river sands of the Urals in Russia. They are rare elements, ruthenium particularly so, their estimated abundances in the earth s crustal rocks being but O.OOOl (Ru) and 0.005 (Os) ppm. However, as in Group 7, there is a marked contrast between the abundances of the two heavier elements and that of the first. 

Collectively known as the coinage metals because of their former usage, these elements were almost certainly the first three metals known to man. All of them occur in the elemental, or native , form and must have been used as primitive money long before the introduction of gold coins in Egypt around 3400 BC. 

Elements dissolved in boron influence its crystal structure. Dissolved impurities also influenee the physical and chemical properties of boron, especially the electrical properties, because boron is a semiconductor. Preparation of solid solutions in jS-rh boron requires a careful choice of crucible material. To avoid contamination, boron nitride or a cold, coinage-metal crucible should be used or the levitation or floating-zone melting techniques applied. 

The reddish metal was already known in prehistoric times. It occasionally occurs as a native metal, but mostly in conspicuous green ores, from which it is extracted relatively easily. It is convenient to work, but not very hard. Not very optimal as a tool ("Otzi the Iceman" had a copper axe with him). Only through the addition of tin is the more useful bronze obtained. Its zinc alloy is the versatile and widely used brass. Copper is one of the coinage metals. Water pipes are commonly made of copper. Its very good thermal and electrical conductivity is commonly exploited (cable ), as well as its durability (roofs, gutters), as the verdigris (basic copper carbonate) protects the metal. Cu phthalocyanines are the most beautiful blue pigments. Seems to be essential to all life as a trace element. In some molluscs, Cu replaces Fe in the heme complex. A 70-kg human contains 72 mg. 

Ans. (a) Pb4 + and Pb2+. (The maximum oxidation state of a group IV element and the state 2 less than the maximum.) (b) Tl3+ and Tl+. (The maximum oxidation state of a group III element and the state 2 less than the maximum.) (c) Sn4+ and Sn2+. (The maximum oxidation state of a group IV element and the state 2 less than the maximum.) (d) Cu+ and Cu2 +. (The maximum oxidation state for the coinage metals is greater than the group number.)... 

The coinage metals are malleable and ductile, and are very good conductors of electricity. They are rather unreactive, and the ways they combine are simpler than those of the other transition elements. They usually combine by losing one, two, or three electrons. 

Figure 1.1 Principal features of the periodic table. The International Union of Pure and Applied Chemistry (IUPAC) now recommends Arabic group numbers 1-18 in place of the traditional Roman I—VIII (A and B). Group names include alkali metals (1), alkaline earth metals (2), coinage metals (11), chalcogens (16), and halogens (17). The main groups are often called the s,p block, the transition metals the d, block elements, and the lanthanides and actinides the / block elements, reflecting the electronic shell being filled. (See inside front cover for detailed structure of the periodic table.)...

Give the notation for the valence-shell configuration of (a) alkali metals (b) Group 13 elements (c) Group 9 transition metals (d) coinage metals (Group 11). 

The elements close to the right-hand edge of the d-block have full d-orbitals. Group 11 contains the coinage metals—copper, silver, and... 

With increasing IEs comes also a general decline in electropositive character. Early elements in each series are thermodynamically extremely reactive towards oxygen and other electronegative elements (although the formation of an inert oxide film may kinetically prevent the solid elements from further oxidation). Later elements are less reactive, 2 trend that culminates in the noble or coinage metals Cu,... 

CID methods have proven to be very useful in measuring the stabilities of clusters of bare transition metal atoms, providing many more thermochemical values than photodissociation methods. In our laboratory, we have used CID to study the cationic clusters of ten different transition metal elements, including TiJ (x=2-22),VJ (x=2-20), CrJ (x=2-21),Mn, FeJ (x=2-19),CoJ (x=2-18),NiJ (x=2—18), and CuJ the second row transition metal clusters of NbJ (x=2-ll) and the third row transition metal clusters of Taj (x=2-4). These results have been summarized and trends analyzed previously [176,177]. CID methods have also been used by Ervin et al. to measure the stabilities of anionic clusters of the coinage metals Cu (x=2-8) [178], Ag (x=2—11) [179], and Au (x=2-7) [180] and group 10 metals Pd [181] and Ptx (x=3-6) [182]. A multiple collision-in-... 

Copper, silver, and gold—the coinage metals—have long been prized for their stability, or lack of reactivity (Figure 8.6). They can even occur uncombined in nature. Active metals do not occur naturally as free elements. 

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