18.2 Occurrence and Preparation of the Representative Metals

18.2 Occurrence and Preparation of the Representative Metals

  • Representative metals, metalloids, and nonmetals are allotropes.
    • There are two allotropes.
    • The allotropes are grey and white.
    • The arrangement of the atoms is the difference between these forms of tin.
    • White tin is stable and can be changed into other metals.
    • The more stable form is gray tin.
    • The tin is brittle and can break into a powder.
    • Tin will break down in cold weather if the spell is long.
    • The gray tin that is first formed starts the change from the spot of origin.
    • This effect is similar to the spread of an illness in a plant or animal, leading people to call it tin disease or tin pest.
  • tin is used in the coating of steel to make tin plate-sheet iron, which is used in tin cans.
  • Bronze and solder are important in tin.
    • There are lead storage batteries in automobiles.
  • The tri-positive ion, Bi3+, is formed by giving up three of its five electrons to active nonmetals.
    • It forms compounds when treated with strong oxidizing agents.
    • Another example of the inert pair effect is the stability of the 3+-oxidation state.
  • Most representative metals are not free elements in nature because of their reactivity.
    • There are many compounds that contain ion of most representative metals.
    • In this section, we will look at the techniques used to separate the metals from the compounds.
  • Salt deposits from ancient seas and silicates are where the metals are found.
    • The alkaline earth metals are silicates and carbonates.
    • The mineral beryl, Be3Al2Si6O18, may be the emerald or aquamarine.
    • The heavier alkaline earth metals occur as silicates, carbonates, and sulfates in seawater.
    • In many types of clay, aluminum is abundant.
    • The lead and thallium ores are the products of weathering of the sulfides, and the oxide cassiterite is the principle tin Ore.
    • The metals that are representative are zinc or aluminum.
  • Ions of metals in groups 1 and 2, along with aluminum, are very difficult to reduce; therefore, it is necessary to prepare these elements by electrolysis.
    • In the isolation of reactive metals, it is useful to use electrolysis to drive unfavorable chemical reactions to completion.
    • Some examples are sodium, aluminum, and magnesium.
  • The passage of a direct current through the cell causes the sodium ion to migrate to the negatively charged cathode and the electrons to be picked up.
    • Chloride ion migrate to a positively charged anode, lose electrons, and undergo oxidation to chlorine gas.
  • The liquid sodium floats to the surface and flows into a collector.
    • The chlorine goes to storage tanks.
  • Chlorine is a valuable product.
  • Pure sodium metal is isolated using a Downs cell.
    • Due to the fact that hydrogen gas forms at the cathode instead of the desired sodium metal, it is not possible to separate sodium from the solution.
    • Liquid sodium metal forms when the temperature is high.
  • The process for preparing aluminum was invented in 1886 by Charles M. Hall, who was a student at Oberlin College.
    • The process was discovered in France by Paul L. T. Heroult.
    • The Hall-Heroult cell is used for the production of aluminum.
  • A molten mixture of cryolite, Na3AlF6, and calcium fluoride, CaF2, is created by heating the hydroxide.
  • Oxygen, carbon monoxide, and carbon dioxide form at the anode when aluminum is reduced to the metal.
  • The production of aluminum involves the use of an electrolytic cell.
  • The other metal that is isolated in large quantities is magnesium.
    • Seawater is the major source of magnesium.
    • The magnesium hydroxide is created by the addition of calcium hydroxide to the water.
    • Adding hydrochloric acid to magnesium hydroxide leaves pure magnesium chloride.
  • Some production facilities are no longer using electrolysis.
    • The Pidgeon process leads to the chemical reduction of magnesium.
  • Chemical reduction is the method of choice for the isolation of elements because it is less expensive than electrolysis.
    • It is possible to reduce the molten chlorides of the metals by using a chemical.
    • The metals formed are more volatile than sodium and can be distilled for collection.
    • The removal of the metal Vapor leads to a shift in the equilibrium to produce more metal.
  • Chemical reduction can be seen in the production of magnesium, zinc, and tin.
  • The majority of the world's magnesium production comes from China.
  • Zinc ores usually contain zinc sulfide, zinc oxide, or zinc carbonate.
    • The zinc contains arsenic, iron, and lead.
    • Pure zinc is produced by careful redistillation.
    • The zinc has a lower boiling point.
    • Zinc is distilled from lead and iron at higher temperatures.
  • The roasting of tin ores removes volatile oxides such as arsenic and sulfur.
    • The oxides of other metals can be removed with the use of hydrochloric acid.