CHEM 1120 1nd Edition Lecture 20Outline of Last Lecture I. Halogensa. Reactive Non-metalsb. Propertiesc. Preparationd. Important compoundse. UsesII. Group 6A – Oxygen Familya. Allotropes of Oxygenb. Oxidesc. Superoxidesd. SulfurOutline of Current Lecture I. Group 6Aa. Sulfur oxides, oxyacids, and oxyanions,b. Se and TeII. Group 5A – Nitrogen familya. Ammoniab. Hydrazinec. Nitrogen oxidesIII. Group 4A – Carbon familya. Carbidesb. SiliconCurrent LectureI. Group 6Aa. Sulfur Oxides, oxyacids, and oxyanionsi. SO2 is a poisonii. Sulfites and bisulfites are added to foods and wines to kill bacteriab. Selenium and Telluriumi. These elements are anions in minerals with Cu, Pb, Ag, and Auii. Naturally found as helical chainsiii. Se not electrically conductive in the dark but quite so in lightII. Group 5A – Nitrogen familyThese 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.a. Nearly all compounds are covalentb. Nitrogen and phosphorus are nonmetals but nitrogen can form N3- anionc. As and Sb are metalloidsd. Metallic Bi forms mostly covalent compounds but does form Bi3+e. Nitrogen and Dinitrogeni. N2 is the most common atmospheric element ii. Boils at -196 degrees Celsius, can be purified from air by fractional distillation iii. N2 has a strong triple bond, most stable homonuclear diatomic moleculeiv. Plants require large amounts of N, can’t use N2v. Large oxidation state range: -3 -> +5f. Ammonia (NH3)i. Has oxidation state -3ii. One of most common N compoundsiii. Colorless gas with strong odor, acutely toxiciv. Liquid = polar with strong H bondingg. Hydrazine (H2N – NH2)i. Sp3 hybridizedii. Long N-N bondiii. Colorless liquid, toxiciv. Good reducing agent and basev. Very reactive with O2 and H2O2h. Fritz Haberi. Received nobel prize in chemistry for NH3 synthesisii. Use catalysts, high P and high Tiii. Enabled Germany to persevere in WWI by providing a source of nitrates for explosivesi. Dinitrogen fixationi. Plants need N but can’t fix N2 into usable form, can convert N2 to NH4+j. Nitrogen oxidesi. Most important1. Nitrous oxide N2Oa. Colorless gas, laughing gas, sweet smell and taste2. Nitric oxide (NO)a. Colorless, important in biological signaling3. Nitrogen dioxide (NO2)a. Toxic, yellow-brown, nasty odor, smog componentk. Phosphorus allotropesl. Compounds of phosphorusi. Hydrides 1. Phosphine (PH3)a. Colorless, pyrophoric gas, very toxic, strong reducing agentii. Halides1. Trihalides (PX3)2. Pentahalides3. Triorganophosphines III. Group 4A – Carbon Familya. C nonmetal, forms covalent compundsb. Metalloids Si and Ge form strong polar covalent bondsc. Metallic Sn and Pb exhibit +2 and +4 oxidation statesd. Allotropes of carboni. Graphite, diamond, fullerenes, nanotubes e. Buckyballi. In 1996 received nobel prize for discovery of fullerenes, C60, looks like soccer ballf. Carbidesi. Carbon combines with metals to form ionic carbidesii. C22-, C4- are strong basesg. Oxides of carboni. CO and CO2h. Carbonic Acid and carbonatesi. Dissolved CO2 in water is in equilibriumi. Cyanidei. C and N bound with triple bond, isoelectronic with CO, very versatile anion, very toxic ii. Binding strongly and irreversibly to Fej. Silicon in electronicsi. Wafersk. Siliconi. Silicon chemistry is quite different from that of Cii. Silicon carbide (SiC) has a diamond-like structureiii. Silicates make up about 90% of earth’s crustiv. Simplest silicate has tetrahedral structuresl. Silicatesi. Chain, double chain, sheet, and frameworksm. Glassesi. Glasses have amorphous, non-crystalline structures, broad m.p. ranges, behave like supercooled liquidsii. Na2O, CaO: not resistant to thermal shock, windows, bottlesiii. PbO: dense, high index of refractionn. Siliconesi. Synthetic polymersIV. Group 3A – Boron