24.2 The p-block elements: metals and nonmetals
Group 3A <ul><li>Boron- occurs naturally in borate minerals ( found in desert U.S.) </li></ul><ul><li>Purified borax – sod...
 
<ul><li>Boron carbide- B 4 C very hard, used in  making machine tools </li></ul><ul><li>Aluminum- most abundant metal in c...
<ul><li>After discovery of an inexpensive way to produce pure Al, use of Al exploded ( it was much cheaper now)-in aircraf...
Carbon and Group 4A <ul><li>C- fundamental element in natural world </li></ul><ul><li>C- has allotropes- diamond and graph...
Graphite <ul><li>Sheets of benzene rings. </li></ul><ul><li>Sheets can slip over each other </li></ul><ul><ul><li>- good l...
Diamond Tetrahedral array of carbon Very hard
Spherical A regular  structure of 5 and 6 member rings. Fullerenes or Buckyballs. C 60
<ul><li>Sn and Pb are metals, fairly unreactive </li></ul><ul><li>Sn- found as SnO 2  in nature- malleable, used in alloys...
Nitrogen and Group 5 <ul><li>N is a nonmetal, gas at rm temp; essential for living things </li></ul><ul><li>80% of air is ...
<ul><li>N 2  is colorless, odorless, tasteless, slightly soluble in water  </li></ul><ul><li>Used to make NH 3 , ammonia i...
<ul><li>P- nonmetal; important in living things (DNA, bones, teeth, ATP) </li></ul><ul><li>Found as phosphate rock </li></...
Oxygen and Group 6A <ul><li>O and S  nonmetals; Se and Te are metalloids; Po is a radioactive, metal that occurs in small ...
Oxygen <ul><li>There are more oxygen atoms in the Earth’s crust, surface waters and atmosphere than atoms of any other ele...
Oxygen production <ul><li>Industrially, oxygen is obtained by liquefying and fractionally distilling air. </li></ul><ul><l...
Oxygen use <ul><li>The major industrial use is in the production of steel.  This accounts for 65-85% of production. </li><...
Physical properties of O 2 <ul><li>O 2  is a colorless, odorless, tasteless gas. </li></ul><ul><li>Solubility. </li></ul><...
Ozone <ul><li>Ozone, O 3 , is an allotrope of molecular oxygen. </li></ul><ul><li>It is prepared by electrical discharge o...
Ozone <ul><li>Ozone is unstable and very reactive,  </li></ul><ul><li>Catalysts and UV light cause it to decompose. </li><...
Ozone <ul><li>Atmospheric ozone. </li></ul><ul><li>Ozone strongly absorbs UV radiation in the 220-290 nm range. </li></ul>...
Ozone <ul><li>Ozone as a disinfectant. </li></ul><ul><li>O 3  is now being used in hospitals, hotels and commercial laundr...
Chemical Properties of O <ul><li>When substances combine w/oxygen the process is called oxidation, mostly the products are...
Sulfur <ul><li>S is a yellow, tasteless, odorless, brittle solid </li></ul><ul><li>Elemental sulfur has more allotropes th...
Sulfur <ul><li>When sulfur is heated, the packing of the S 8  molecules changes around 96  o C. </li></ul><ul><li>Another ...
Sulfur <ul><li>When liquid sulfur polymerizes, its viscosity increases by a factor of at least 10 000. </li></ul><ul><li>T...
Sulfur reactivity <ul><li>Sulfur is quite a reactive element. </li></ul><ul><li>It will react will all elements except nit...
Sulfur production <ul><li>Free sulfur occurs in rock over salt domes near the coast of East Texas and Louisiana and under ...
Sulfuric acid and sulfates <ul><li>Sulfuric acid </li></ul><ul><li>It is the cheapest strong acid. </li></ul><ul><li>Conce...
<ul><li>Produced by the contact process-Sulfur is burned in air to form sulfur dioxide, then sulfur dioxide combines w/mor...
Sulfuric acid and sulfates <ul><li>Some important sulfates </li></ul><ul><li>Aluminum sulfate </li></ul><ul><ul><li>Al 2 (...
Oxides of sulfur <ul><li>A number of oxides are known to exist but SO 2  and SO 3  are the most stable and important. </li...
Oxides of sulfur <ul><li>Sulfur trioxide - SO 3 </li></ul><ul><li>It is a liquid under ordinary conditions. Difficult to h...
Other Group 6A elements <ul><li>Selenium is a semi-conductor; poor conductor of electricity in dark, good in light; this m...
Halogens, Group 7A <ul><li>Do not exist in nature uncombined, but their compounds are abundant; many of their sodium salts...
<ul><li>Most are water soluble </li></ul><ul><li>All hydrogen halides, except HF, form strong acids ( hi ionization) </li>...
Chlorine <ul><li>Chlorine is 10th in the Top 50 list of chemicals produced. </li></ul><ul><li>It is a yellow, pungent and ...
Chlorine <ul><li>Uses </li></ul><ul><li>About 70% of all chlorine is used in the chemical industry.  In many cases, the fi...
Hydrochloric acid <ul><li>HCl is 27th on the Top 50 list of chemicals. </li></ul><ul><li>Most is produced as a by-product ...
Chlorine oxides <ul><li>Two oxides are made industrially, dichlorine monoxide and chlorine dioxide. </li></ul><ul><li>Both...
Fluorine <ul><li>Made by electrolyzing an ice-cold solution of KF in HF (1886- Henri Moissan) </li></ul><ul><li>Most chemi...
Iodine and Bromine <ul><li>Br is obtained from  sea water and salt-well brines </li></ul><ul><li>2NaBr (aq)  + Cl 2(g) ---...
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Ch 24 sec2

  1. 1. 24.2 The p-block elements: metals and nonmetals
  2. 2. Group 3A <ul><li>Boron- occurs naturally in borate minerals ( found in desert U.S.) </li></ul><ul><li>Purified borax – sodium tetraborate decahydrate (Na 2 B 4 O 7 . 10H 2 O) is soft colorless and crystalline; found in glass, ceramics and fertilizers; used to soften water, disinfect, or as flux </li></ul><ul><li>Pure Boron- black, hard, lustrous, but brittle- it is a metalloid, semiconductor </li></ul><ul><li>prepared by: B 2 O 3 +3Mg ----2B + 3MgO </li></ul>
  3. 4. <ul><li>Boron carbide- B 4 C very hard, used in making machine tools </li></ul><ul><li>Aluminum- most abundant metal in crust; is not found in pure form in crust- bauxite(Al 2 O 3) and corundum (impure Al 2 O 3 ) are common minerals </li></ul><ul><li>Valuable properties: strength, ductility, low density, corrosion resistance, high electrical conductivity, forms resistant oxide coating- used for structures and manufacturing </li></ul>Aluminum and Group 3A
  4. 5. <ul><li>After discovery of an inexpensive way to produce pure Al, use of Al exploded ( it was much cheaper now)-in aircraft, cookware, cans, foil etc. </li></ul><ul><li>Other Group 3A elements are rare- gallium used in thermometers and as semiconductor </li></ul>Aluminum and Group 3A
  5. 6. Carbon and Group 4A <ul><li>C- fundamental element in natural world </li></ul><ul><li>C- has allotropes- diamond and graphite and few more ( bucky balls, nanotubes) </li></ul><ul><li>C- nonmetal </li></ul><ul><li>Si- Si fundamental element in geological world- SiO 2 ( silicon dioxide) is quartz </li></ul><ul><li>Si and Ge are semi-conductors (metalloids) ; good insulators but at hi T they conduct electricity- used in transistors and photocells </li></ul>
  6. 7. Graphite <ul><li>Sheets of benzene rings. </li></ul><ul><li>Sheets can slip over each other </li></ul><ul><ul><li>- good lubricant </li></ul></ul>
  7. 8. Diamond Tetrahedral array of carbon Very hard
  8. 9. Spherical A regular structure of 5 and 6 member rings. Fullerenes or Buckyballs. C 60
  9. 10. <ul><li>Sn and Pb are metals, fairly unreactive </li></ul><ul><li>Sn- found as SnO 2 in nature- malleable, used in alloys ( bronze is Sn and Cu) and solder (Sn and Pb); SnF 2 - stannous fluoride is used in toothpaste </li></ul><ul><li>Pb- low m. pt. ; refined from mineral galena (PbS); used in plumbing and lead storage batteries </li></ul><ul><li>Pb has health concerns- no more leaded gasoline or lead-based paints </li></ul>Carbon and Group 4A
  10. 11. Nitrogen and Group 5 <ul><li>N is a nonmetal, gas at rm temp; essential for living things </li></ul><ul><li>80% of air is N 2 , but most living things cannot use pure nitrogen- bacteria “fix” nitrogen into usable form </li></ul><ul><li>N 2 is commercially obtained 2 ways, both from air: 1) fractional distillation ( nitrogen boils off first) </li></ul><ul><li>2) Air is moved over hot coke ( C) and oxygen is removed and forms CO 2 leaving nitrogen </li></ul>
  11. 12. <ul><li>N 2 is colorless, odorless, tasteless, slightly soluble in water </li></ul><ul><li>Used to make NH 3 , ammonia in Haber process (pg 715), and nitric acid </li></ul><ul><li>Ammonia- strong odor, colorless gas, soluble in water, slightly basic; used in cleaning products, fertilizers, refrigerant </li></ul><ul><li>Nitric acid ( can be made from ammonia)-used in etching, fertilizers, dyes and explosives </li></ul>Nitrogen and Group 5
  12. 13. <ul><li>P- nonmetal; important in living things (DNA, bones, teeth, ATP) </li></ul><ul><li>Found as phosphate rock </li></ul><ul><li>In pure form- 2 types of P- red and white </li></ul><ul><li>white is very reactive and stored under water; red is less reactive-used in matches </li></ul><ul><li>Arsenic, Bi and antimony occur in nature as sulfide minerals </li></ul><ul><li>Sb and Bi expand when heated- used in alloys ( printing presses) </li></ul>Nitrogen and Group 5
  13. 14. Oxygen and Group 6A <ul><li>O and S nonmetals; Se and Te are metalloids; Po is a radioactive, metal that occurs in small amounts </li></ul>
  14. 15. Oxygen <ul><li>There are more oxygen atoms in the Earth’s crust, surface waters and atmosphere than atoms of any other element. </li></ul><ul><li>Molecular oxygen makes up 23% by mass of the atmosphere. </li></ul><ul><li>Oxygen in compounds make up 46% by mass of the crust and upper mantle. </li></ul><ul><li>In surface waters, oxygen accounts for 86% by mass. </li></ul>
  15. 16. Oxygen production <ul><li>Industrially, oxygen is obtained by liquefying and fractionally distilling air. </li></ul><ul><li>Worldwide production of oxygen is almost 2 x 10 11 pounds each year. This is only 10 -5 % of the oxygen in the atmosphere. </li></ul><ul><li>Molecular oxygen is continuously being made via photosynthesis by plants that require carbon dioxide. </li></ul><ul><li>Animals breathe in oxygen and breathe out carbon dioxide. </li></ul>
  16. 17. Oxygen use <ul><li>The major industrial use is in the production of steel. This accounts for 65-85% of production. </li></ul><ul><li>Large quantities of oxygen are also used to produce titanium(IV) oxide, a white pigment. </li></ul><ul><li>Oxygen is also used as an oxidizing agent to power the space shuttle, for sewage treatment and various industrial processes. </li></ul><ul><li>It also is used in medicine. </li></ul>
  17. 18. Physical properties of O 2 <ul><li>O 2 is a colorless, odorless, tasteless gas. </li></ul><ul><li>Solubility. </li></ul><ul><li>Only slightly soluble in water. </li></ul><ul><li>Less soluble in salt water than fresh water. </li></ul><ul><li>Increasing temperature will decrease solubility in water. </li></ul><ul><li>It is paramagnetic (weakly magnetic) </li></ul>
  18. 19. Ozone <ul><li>Ozone, O 3 , is an allotrope of molecular oxygen. </li></ul><ul><li>It is prepared by electrical discharge or UV light on molecular oxygen. </li></ul><ul><li>3O 2 (g) 2O 2 (g) </li></ul><ul><li>Ozone is a diamagnetic blue gas with a characteristic odor. Concentrations as low as 0.01 ppm can be detected by odor. </li></ul>UV or silent electrical discharge
  19. 20. Ozone <ul><li>Ozone is unstable and very reactive, </li></ul><ul><li>Catalysts and UV light cause it to decompose. </li></ul><ul><li>2O 3 (g) 3O 2 (g) </li></ul><ul><li>It is also a more powerful oxidizing agent that molecular oxygen. In acidic solutions, it is one of the most powerful oxidizing agents known. </li></ul><ul><li>O 3 (g) + 2H + + 2e - O 2 (g) + H 2 O (l) E o = +2.07 V </li></ul>catalyst or UV
  20. 21. Ozone <ul><li>Atmospheric ozone. </li></ul><ul><li>Ozone strongly absorbs UV radiation in the 220-290 nm range. </li></ul><ul><li>The ozone layer is stratospheric-level O 3 . It protects the Earth’s surface from the Sun’s intense UV radiation. </li></ul><ul><li>Tropospheric level O 3 , however, is harmful. It contributes to smog formation and causes rubber to crack. </li></ul>
  21. 22. Ozone <ul><li>Ozone as a disinfectant. </li></ul><ul><li>O 3 is now being used in hospitals, hotels and commercial laundries. </li></ul><ul><li>It is also used to purify drinking water. </li></ul><ul><li>Advantage </li></ul><ul><li>After reaction, only O 2 remains unlike when Cl 2 is used. Chlorine can form chlorocarbons. </li></ul><ul><li>Disadvantage </li></ul><ul><li>No residual protection. Since it rapidly decomposes, there is no protection after water treatment. </li></ul>
  22. 23. Chemical Properties of O <ul><li>When substances combine w/oxygen the process is called oxidation, mostly the products are oxides </li></ul><ul><li>Usually this occurs when you heat the elements in the presence of oxygen </li></ul><ul><li>Oxides of metals are usually solids, and can form a basic water solution </li></ul><ul><li>Oxides of nonmetals can be a solid, liquid or gas and tend to form acidic water solutions </li></ul>
  23. 24. Sulfur <ul><li>S is a yellow, tasteless, odorless, brittle solid </li></ul><ul><li>Elemental sulfur has more allotropes than any other elements. </li></ul>The S-S bond is the third strongest single bond between the same kind of atoms. At room temperature, the most common form is rhombic, consisting of eight member rings.(S 8 )
  24. 25. Sulfur <ul><li>When sulfur is heated, the packing of the S 8 molecules changes around 96 o C. </li></ul><ul><li>Another form of sulfur is monoclinic sulfur. It is stable between 96-119 o C. </li></ul><ul><li>When liquid sulfur is heated (160-195 o C), it polymerizes into chains up to 200 000 S long. </li></ul>160-195 o C 160-195 o C
  25. 26. Sulfur <ul><li>When liquid sulfur polymerizes, its viscosity increases by a factor of at least 10 000. </li></ul><ul><li>This is because the long chains tend to get tangled up in each other. </li></ul>
  26. 27. Sulfur reactivity <ul><li>Sulfur is quite a reactive element. </li></ul><ul><li>It will react will all elements except nitrogen, tellurium, iodine, iridium, platinum, gold and the noble gases. </li></ul><ul><li>Heating may be necessary to bring about a reaction. </li></ul><ul><li>Compounds of all elements except the noble gases with sulfur are known. </li></ul><ul><li>Although it is reactive, sulfur can be found in nature in free as well as combined form. </li></ul>
  27. 28. Sulfur production <ul><li>Free sulfur occurs in rock over salt domes near the coast of East Texas and Louisiana and under the Gulf of Mexico. It is mined by the Frasch process. </li></ul>Superheated water Compressed hot air Sulfur Molten Sulfur
  28. 29. Sulfuric acid and sulfates <ul><li>Sulfuric acid </li></ul><ul><li>It is the cheapest strong acid. </li></ul><ul><li>Concentrated sulfuric acid is an oxidizing agent -- but only when hot. </li></ul><ul><li>Cu (s) + 2H 2 SO 4 (conc) CuSO 4 (aq) + 2H 2 O (l) + SO 2 (g) </li></ul><ul><li>When cold, it will not oxidize copper. </li></ul><ul><li>It is such a powerful dehydrating agent, it can char many organic substances (sugar dehydration-products are C and water </li></ul>heat
  29. 30. <ul><li>Produced by the contact process-Sulfur is burned in air to form sulfur dioxide, then sulfur dioxide combines w/more oxygen in presence of vanadium(V)oxide to form sulfur trioxide; sulfur trioxide combines w/water to form sulfuric acid </li></ul><ul><li>Dilute sulfuric acid combines w/ metals, oxides, hydroxides or carbonates to form sulfate salts </li></ul>Sulfuric acid and sulfates
  30. 31. Sulfuric acid and sulfates <ul><li>Some important sulfates </li></ul><ul><li>Aluminum sulfate </li></ul><ul><ul><li>Al 2 (SO 4 ) 3 </li></ul></ul><ul><ul><li>Produced from Al 2 O 3 . 2 H 2 O (bauxite) </li></ul></ul><ul><ul><li>Used to treat water </li></ul></ul><ul><ul><li>Used to size paper - fill pores. </li></ul></ul><ul><li>Ammonium sulfate </li></ul><ul><ul><li>(NH 4 ) 2 SO 4 </li></ul></ul><ul><ul><li>Produced by reaction of H 2 SO 4 and NH 3 </li></ul></ul><ul><ul><li>Used in fertilizers. </li></ul></ul>
  31. 32. Oxides of sulfur <ul><li>A number of oxides are known to exist but SO 2 and SO 3 are the most stable and important. </li></ul><ul><li>Sulfur dioxide - SO 2 </li></ul><ul><li>Colorless gas with a sharp odor; harmful to animal and plant life; produced by combustion of sulfur-containing fuels, volcanoes and air oxidation of marsh gases. </li></ul><ul><li>Is oxidized to SO 3 by air oxidation. </li></ul>
  32. 33. Oxides of sulfur <ul><li>Sulfur trioxide - SO 3 </li></ul><ul><li>It is a liquid under ordinary conditions. Difficult to handle because it reacts vigorously with many materials. It is an anhydride of sulfuric acid. </li></ul><ul><li>SO 3 (g) + H 2 O (l) H 2 SO 4 (l) </li></ul><ul><li>It, along with NO 2 , HCl, SO 2 , accounts for the acidity of acid rain. </li></ul>
  33. 34. Other Group 6A elements <ul><li>Selenium is a semi-conductor; poor conductor of electricity in dark, good in light; this makes it useful in photovoltaic cells, also used in photocopying machines </li></ul><ul><li>Te is rare, and its compounds are toxic </li></ul>
  34. 35. Halogens, Group 7A <ul><li>Do not exist in nature uncombined, but their compounds are abundant; many of their sodium salts (NaF, NaI,NaCl,NaBr) are found in seawater; CaF 2 is fluorspar- a mineral </li></ul><ul><li>All are nonmetals </li></ul><ul><li>Fluorine and chlorine are gases and yellowish to green; bromine is dark red liquid, iodine is a black solid ( vapors are purple) </li></ul><ul><li>All are very reactive ( they only need 1e - ) </li></ul>
  35. 36. <ul><li>Most are water soluble </li></ul><ul><li>All hydrogen halides, except HF, form strong acids ( hi ionization) </li></ul>Halogens, Group 7A
  36. 37. Chlorine <ul><li>Chlorine is 10th in the Top 50 list of chemicals produced. </li></ul><ul><li>It is a yellow, pungent and highly corrosive gas. </li></ul><ul><li>Cl 2 is too reactive to occur free in nature. </li></ul><ul><li>Chlorine occurs mostly as sodium chloride in salt waters and mineral deposits. </li></ul><ul><li>Industrial preparation - electrolysis of NaCl. </li></ul><ul><li>2NaCl (aq) + 2H 2 O (l) 2NaOH (aq) + Cl 2 (g) + H 2 (g) </li></ul>
  37. 38. Chlorine <ul><li>Uses </li></ul><ul><li>About 70% of all chlorine is used in the chemical industry. In many cases, the final compound does not even contain chlorine. </li></ul><ul><li>About 20% is used to bleach wood pulp and paper to make it white. </li></ul><ul><li>Another 5% is used for water treatment. </li></ul><ul><li>Household bleach is made by allowing chlorine to react with NaOH. </li></ul><ul><li>Cl 2 (aq) + 2NaOH (aq) NaOCl (aq) + NaCl (aq) + H 2 O (l) </li></ul><ul><li>Also used to make vinyl chloride and polyvinyl chloride (PVC) </li></ul>
  38. 39. Hydrochloric acid <ul><li>HCl is 27th on the Top 50 list of chemicals. </li></ul><ul><li>Most is produced as a by-product of the chlorination of organic compounds. </li></ul><ul><li>CH 4 (g) + 2Cl 2 (g) CH 2 Cl 2 (l) + 2HCl (g) </li></ul><ul><li>Hydrochloric acid is a strong acid. </li></ul><ul><li>Concentrated HCl is produced by saturation of water - approximately 12M. </li></ul><ul><li>In the hardware store, you would find it under the name muriatic acid. </li></ul>
  39. 40. Chlorine oxides <ul><li>Two oxides are made industrially, dichlorine monoxide and chlorine dioxide. </li></ul><ul><li>Both are used for bleaching paper and flour. </li></ul><ul><li>A radical, ClO, has been studied as a result of the role it plays in destruction of the ozone layer. Using Freon-12 as an example, CCl 2 F 2 : </li></ul>
  40. 41. Fluorine <ul><li>Made by electrolyzing an ice-cold solution of KF in HF (1886- Henri Moissan) </li></ul><ul><li>Most chemically reactive of all nonmetals </li></ul><ul><li>Strong oxidizing agent </li></ul><ul><li>Forms compounds w/ elements except He, Ne, Ar </li></ul><ul><li>HF acid is used to etch glass </li></ul><ul><li>Used to separate the isotopes of Uranium </li></ul>
  41. 42. Iodine and Bromine <ul><li>Br is obtained from sea water and salt-well brines </li></ul><ul><li>2NaBr (aq) + Cl 2(g) ------2NaCl (aq) + Br 2(l) </li></ul><ul><li>Iodine used to be extracted from ashes of seaweeds; now it is produced from sodium iodate ( NaIO 3 ) </li></ul><ul><li>Iodine is necessary for the thyroid gland to work properly </li></ul>

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