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Lecture 18. The d -Block Elements. I-III B groups

Lecture 18. The d -Block Elements. I-III B groups. PhD. Halina Falfushynska. Group 1B: Cu, Ag, and Au. The group 1B metals are called coinage metals because of their use in money. Group 1B is often found as the free metals, and are difficult to oxidize.

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Lecture 18. The d -Block Elements. I-III B groups

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  1. Lecture 18. The d-Block Elements.I-III B groups PhD. Halina Falfushynska

  2. Group 1B: Cu, Ag, and Au • The group 1B metals are called coinage metals because of their use in money. • Group 1B is often found as the free metals, and are difficult to oxidize. • Residential electrical wiring is almost always made of copper. • Silver and gold are used in electronic components, but the primary use of gold is as a monetary reserve for individuals and nations.

  3. Azurite (Cu3(CO3)2(OH)2)

  4. Cu extraction • Chalcopyrite (CuFeS2) and chalcocite (Cu2S) minerals are concentrated from crushed ores to the level of 10–15% copper by froth flotation or bioleaching. • 2СuFeS2 + O2 Cu2S + FeS + SO2 • Heating this material with silica in flash smelting removes much of the iron as slag. FeO + SiO2FeSiO3 • The copper matte consisting of Cu2S is convert into oxides: 2 Cu2S + 3 O2 → 2 Cu2O + 2 SO2 • The cuprous oxide is converted to blister copper upon heating: 2 Cu2O → 4 Cu + O2

  5. Gold extraction • 4Au + 8NaCN + 2H2O + O2 4Na[Au(CN)2]+ 4NaOH • 2Na[Au(CN)2] + Zn  Na2[Zn(CN)4] + 2Au GOLD NUGGET FROM JAPAN

  6. Group 1B: Cu, Ag, and Au • None of these metals dissolves in HCl. Cu and Ag dissolve in HNO3 and H2SO4 Cu + 2H2SO4CuSO4 + SO2 + 2H2O Ag + 2HNO3 AgNO3 + NO2 + H2O 2Ag + 2H2SO4Ag2SO4 + SO2 +2H2O • Gold requires aqua regia—a mixture of HCl and HNO3—to dissolve. Au + HNO3 + 4HCl  H[AuCl4] + NO + 2H2O

  7. Properties of Group 1B • Gold resists air oxidation. Silver forms Ag2S (black) and copper forms Cu(OH)2·CuCO3 (green) in moist air. 2Ag + H2S  Ag2S + H2 ---Gold interacts with iodine 2Au + I2 2AuI 2AuI + NaHSO3 + H2O  2Au + NaHSO4 + 2HI ---AgNO3 + CuCu(NO3)2 + Ag

  8. Test reaction for copper • Сu2+ + S2–CuS – black ppt; • Cu2+ + 2OH– Cu(OH)2 – blue ppt • Сu(OH)2CuO + H2O – black ppt; • 2Cu2+ + 2SO42– + 2NH4OH  Cu2(OH)2SO4 + 2NH4+ + SO42– – green ppt • Cu2(OH)2SO4 + 2NH4+ + 6NH3 2[Cu(NH3)4]2+ + SO42– + 2H2O – deep blueppt; • Carbonates of alkali metals with Cu2+form greenish ppt Cu2(OH)2CO3

  9. Biological role of copper • Copper proteins have diverse roles in biological electron transport and oxygen transportation, processes that exploit the easy interconversion of Cu(I) and Cu(II). • Copperisalsoacomponentofotherproteinsassociatedwiththeprocessingofoxygen (cytochromecoxidase, superoxidedismutases) • Copper is an essential trace element in plants and animals, but not some microorganisms

  10. Biological role of copper • Because of its role in facilitating iron uptake, copper deficiency can produce anemia-like symptoms, neutropenia, bone abnormalities, hypopigmentation, impaired growth, increased incidence of infections, osteoporosis, and abnormalities in glucose and cholesterol metabolism. Conversely, an accumulation of copper in body tissues causes Wilson's disease. • Copper doorknobs are used by hospitals to reduce the transfer of disease, and Legionnaires' disease is suppressed by copper tubing in plumbing systems

  11. Application of Group 1B • CuSO4·5 H2O is used in electroplating and batteries. Copper(II) is an essential element at low concentrations but is toxic at higher concentrations and is used as a pesticide. • AgNO3 is used in photography, silver plating, and in silvering mirrors. • Gold compounds are used in electroplating, photography, medicinal chemistry, and in ruby glass and ceramics.

  12. Group 12 element

  13. Zinc production • Roasting converts the zinc sulfide concentrate produced during processing to zinc oxide: 2 ZnS + 3 O2 → 2 ZnO + 2 SO2 • For further processing two basic methods are used: pyrometallurgy or electrowinning. 2 ZnO + C → 2 Zn + CO2 2 ZnO + 2 CO → 2 Zn + 2 CO2

  14. Electrowinning processing • Electrowinning processing leaches zinc from the ore concentrate by sulfuric acid: • ZnO + H2SO4 → ZnSO4 + H2O • After this step electrolysis is used to produce zinc metal. • 2 ZnSO4 + 2 H2O → 2 Zn + 2 H2SO4 + O2

  15. Typical reaction for zinc • Reaction of zinc with air: 2Zn(s) + O2(g) → 2ZnO(s) • Reaction of zinc with water – no reaction! • Reaction of zinc with the halogens Zn(s) + Br2(g) → ZnBr2(s); Zn(s) + I2(g) → ZnI2(s) • Reaction of zinc with acids Zn(s) + H2SO4(aq) → Zn2+(aq) + SO42-(aq) + H2(g) • Reaction of zinc with bases [Zn(OH)4]2-

  16. Biological role of zinc • In humans, zinc plays "ubiquitous biological roles".It interacts with "a wide range of organic ligands", and has roles in the metabolism of RNA and DNA, signal transduction, and gene expression. It also regulates apoptosis. A 2006 study estimated that about 10% of human proteins (2800) potentially bind zinc, in addition to hundreds which transport and traffic zinc; a similar in silico study in the plant Arabidopsis thaliana found 2367 zinc-related proteins. • There are 2–4 grams of zinc distributed throughout the human body. Most zinc is in the brain, muscle, bones, kidney, and liver, with the highest concentrations in the prostate and parts of the eye. Semen is particularly rich in zinc, which is a key factor in prostate gland function and reproductive organ growth.

  17. Dietary intake of zinc • In the U.S., the Recommended Dietary Allowance (RDA) is 8 mg/day for women and 11 mg/day for men. Median intake in the U.S. around 2000 was 9 mg/day for women and 14 mg/day in men. Oysters, lobster and red meats, especially beef, lamb and liver have some of the highest concentrations of zinc in food.

  18. zinc gluconate Zinc supplement • Zincis included in most single tablet over-the-counter daily vitamin and mineral supplements. Preparations include zinc oxide, zinc acetate, and zinc gluconate. • It is believed to possess antioxidant properties, which may protect against accelerated aging of the skin and muscles of the body; studies differ as to its effectiveness. • Zinc also helps speed up the healing process after an injury.

  19. zinc glycinate Zinc supplement • A 1998 review concluded that zinc oxide, one of the most common supplements in the United States, and zinc carbonate are nearly insoluble and poorly absorbed in the body. For fortification, however, a 2003 review recommended zinc oxide in cereals as cheap, stable, and as easily absorbed as more expensive forms. • A 1987 study found that zinc picolinate was better absorbed than zinc gluconate or zinc citrate. However, a study published in 2008 determined that zinc glycinate is the best absorbed of the four dietary supplement types available.

  20. Zinc deficiency • Nearly two billion people in the developing world are deficient in zinc. In children it causes an increase in infection and diarrhea, contributing to the death of about 800,000 children worldwide per year. The World Health Organization advocates zinc supplementation for severe malnutrition and diarrhea. • Zinc supplements help prevent disease and reduce mortality, especially among children with low birth weight or stunted growth

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