The Coinage Metals: Copper, Silver, and GoldTable of contents
The “coinage metals”, copper, silver, and gold, have held great importance in societies throughout history, both symbolically and practically. For centuries, silver and gold have been worn by royalty to parade their wealth and power. On occasion, these metals were even used in art; during the height of the Byzantine Empire, artists would use gold leaf in mosaics and paintings of royalty as well as in renderings of religious figures, which further demonstrated the power of the individuals represented in these masterpieces.
IntroductionOn a more practical note, these metals are also an integral part of the United States' monetary system, hence the nickname of the "coinage metals".For a good part of the 20th century, the United States functioned on the "gold standard", which basically meant that the dollar was used as a paper representation of a certain amount of gold.Although this system has been discarded, gold and silver are still traded today. Group 11 MetalsCopper, silver, and gold have been chosen as currency for so long because they are durable and they do not readily react with many other materials. They generally do not oxidize in air, unless it is particularly moist in copper's case. These metals also display high levels of the physical properties of metals; copper, silver, and gold are all particularly malleable, ductile and are also good conductors. These metals use their d orbital in chemical bonding, just like other transition metals and so they exist in several oxidation states, which can be seen in the table listing several of the properties of the coinage metals. They can also form complex ions and demonstrate paramagnetism. Table 1: Some properties of Copper, Silver, and Gold
Copper (Cu)
The element copper is used in a variety of ways, including agriculturally, industrially and even in our own bodies. Small amounts of copper are vital to life. It is found in the several tissues and helps certain enzymes function. However, in larger doses, it becomes toxic; thus, copper is a popular component of many pesticides, usually CuSO4• 5 H2O. Copper sulfate is also used in batteries as well as electroplating. It is also popularly used in wiring and piping, since it is such a good conductor and is highly malleable. Although copper is somewhat resistant to corrosion, in air with high levels of moisture, it does corrode but into a copper carbonate which incidentally protects the metal beneath it.
2 Cu(s) + H2O(g) + CO2(g) + O2 → Cu2(OH)2CO3(s) Silver (Ag)
Silver is also a very popular metal. Like gold, silver is a rare metal and holds great value and is also traded in similar markets. Silver is also a popular metal to make jewelry with because of both its rarity and malleability. For some time, silver was also used in dentistry, although it had to be mixed with mercury because it is not quite as malleable as gold. Silver is also a good conductor and is used in electroplating. It is also used in the manufacturing of batteries as well as a catalyst. Silver also played a vital role in photography and consequently, medicine. The first camera-like apparatus was developed during the Middle Ages, but they had no way to make the captured images permanent. Then during the 19th century, the first permanent photos were developed using silver nitrate coated glass plates, which were used as negatives, and modern photography soon developed. However, this process is quickly becoming obsolete due to the emergence of digital photography. The development of permanent photography catalyzed the development of modern medicine. As a result of permanent photography and the silver halides used in its development, William Conrad Roentgen was able to use radiation to create a picture of a person's skeleton, making it easier for doctors to diagnose their patients. Even though coinage metals are known to be resistant to air oxidation, silver will tarnish due to the 2Ag(s) + S(g) → Ag2S (s) Gold (Au)
Gold, like the other coinage metals, is popularly used. It is commonly used to make jewelry, and it was also popularly used in dentistry in the past before more advanced replacements came into the market. This is because it is the most malleable of all metals and does not readily react with the air. Gold can also be hammered into thin sheets, or gold leaf, and is often used in electroplating. Gold is also quite rare and therefore holds great value all over the world. For this reason, gold is not used in piping. For the same reason, it was used as a type of currency. As mentioned before, the United States used to function on the gold standard, but that was later discarded for the current method. Even though we no longer operate on the gold standard, gold bars are still traded today in certain markets. Gold can also be used medicinally. It has been found to help those suffering from severe rheumatoid arthritis as an anti-inflammatory drug. Reactions with acidsCu and Ag are able to react with H2SO4(aq) or HNO3(aq) Thus shifting the oxidation numbers of Cu and Ag to Cu2+ and Ag+. However, Au will not react with either H2SO4(aq) or HNO3(aq), rather it will react with what is called aqua water, which is one part HNO3 and three parts HCl. For example, Au(s) + 4H+(aq) + NO3-(aq) + 4Cl-(aq) → [AuCl4]-(aq) + 2H2O(l) + NO(g) Note: The group 11 metals do not react with hydrochloric acid. References
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Synopsis: Copper,silver, and gold are often sold for a large profit in the form of jewelry and coins. They are resistant to corrosion and have the characteristics of the metals protect them from oxidizing. Copper is often used in piping and electrical wiring. Gold can be found in household objects such as plates and door knobs. Silver is used is used in dentistry to form crowns and to make silverware. The three metals have d orbital bonding which allows for differing oxidation states and paramagnetism to occur. This strongly effects their properties such as malleability and ductility. Copper is commonly used in batteries because it is a strong conductor. Silver is commonly used is the lab setting for the precipitation of anions and in battery production. Gold is used for electroplating, glass production, and photography.
Keywords: Looked up the the words Copper, Gold and Silver on Google. There appears to be no cases of plagariasm.
Review Details: The module was not lacking any important information and is very informative. The overall length is perfect, because it gets the message across and does not provide too much information. You may want to add a few videos too make the module a bit more effective
Correction: I rephrased the sentence "The reason why copper, silver and gold has been the preferred metals throughout many centuries is because these metals are resistant to corrosion and are strong and durable" to eliminate word repetition and changed the word has to have. edited 00:47, 5 Dec 2009