Chem 1120 1st Edition Lecture 21Outline of Last Lecture I. Noble GasesII. HalogensIII. Oxygen FamilyOutline of Current Lecture I. Other Group 6A ElementsII. Nitrogen FamilyIII. Allotropes/Carbon Family/Boron FamilyCurrent Lecture I. Elements in Group 6A have oxidation states of -2, as well as several positive oxidation states, and can have expanded octetsS (Sulfur) brittle, soft yellow solid with low melting point that facilitates its melting in rock with hot steam and transport to surface as emulsion (Frasch process), has a large oxidation number range, -2 to +6Organic compounds of sulfur: Compounds with SH groups are called thiols; have nasty intense odorsInorganic Sulfides: also found in some protein active sites, especially in electron transferIron Pyrite, FeS, is an inorganic sulfide, pyrites contain the disulfide ionDisulfides are an important structural feature in proteins, cysteine SH groups from different sites in the protein react to form S-S bond that “staples” protein together, improving stabilitySulfur oxides, oxyacids, and oxyanions: SO2 is a poison, particularly to lower organisms, it’s used to sterilize dried fruit and wine by dissolving in waterThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Sulfuric acid is a versatile diprotic acid, hot concentrated (98%) sulfuric acid is a strong oxidizing agent and a strong acid, used in production of phosphate fertilizer, petroleum refining, manufacture of detergents, dyes, other chemicalsSelenium and Tellurium: these elements are anions in minerals with Cu, Pb, Ag, and Au, they are naturally found as helical chains of atoms, selenium is not electrically conductive in the dark, but quite so in light II. Nearly all compounds of the nitrogen family are covalent, N and P are nonmetals, and As and Sb are metalloids, metallic Bi forms mostly covalent compounds Nitrogen (N2) is the most common atmospheric element, dinitrogen boils at -196 oC, it creates a triple bond and is the most stable homonuclear diatomic moleculeAmmonia (N oxidation number = -3), one of the most common N compounds,by-product of urea catabolism, colorless gas with strong acrid odor; acutely toxic, as a liquid it is polar with strong H bondingHaber-Bosch process uses catalysts and high P and high T, for NH3 synthesisDinitrogen fixation: plants need N but most cannot “fix” N2 into usable form. Blue-green algae and symbiotic bacteria on roots of soybeans, alfalfa, and clover convert N2 to NH4+ at standard T and PMost important oxides of N: N2O, NO, NO2 III. Phosphorous allotropes, P4, P4O6, or P4O10Phosphates used in many products: toothpaste, feritlizer, rock, etcGroup 4A, Carbon Family:Carbon (C) is nonmetal, forms covalent compoundsMetalloids Silicon (Si) and Germanium (Ge) form strong polar covalent bonds,silicon is very important in geochemistry, electronicsMetallic Tin (Sn) and Lead (Pb) exhibit +2 and +4 oxidation statesCarbon has several allotropes: graphite, diamond, fullerenes, carbon nanotubes, graphene, buckyballOccurs in nature as carbonates, coal, petroleum, and natural gasCarbides: carbon combines with metals to form ionic carbides, very reactive because the carbon prefers covalenceOxides of Carbon: carbon monoxide, carbon dioxideCyanide, C and N bound together with a triple bond, very toxic, isoelectronic with COThere are chains, double chains, sheets, and framework silicates Silicones are synthetic polymers. Chain, sheet, and framework silicones are produced commerciallyGlasses have amorphous, non-crystalline structures, broad melting point ranges; behave like supercooled liquidsGroup 3A Boron Family:Metalloid Boron (B) forms covalent compounds; common compounds include boric acid and boraxAluminum (Al) is a typical metal with compounds predominantly in the +3 oxidation stateGallium (Ga), Indium (In), and Thallium (Tl, poisonous) exhibit +1, +3 oxidation statesElectron deficient boron compounds accept a pair of electrons from a donor, many boron-nitrogen compounds are analogous to C compoundsBoranes (boron hydrides) have novel structures, weirdly