CHEM 1120 Edition 1nd Lecture 20 Outline of Last Lecture I Halogens a Reactive Non metals b Properties c Preparation d Important compounds e Uses II Group 6A Oxygen Family a Allotropes of Oxygen b Oxides c Superoxides d Sulfur Outline of Current Lecture I Group 6A a Sulfur oxides oxyacids and oxyanions b Se and Te II Group 5A Nitrogen family a Ammonia b Hydrazine c Nitrogen oxides III Group 4A Carbon family a Carbides b Silicon Current Lecture I II Group 6A a Sulfur Oxides oxyacids and oxyanions i SO2 is a poison ii Sulfites and bisulfites are added to foods and wines to kill bacteria b Selenium and Tellurium i These elements are anions in minerals with Cu Pb Ag and Au ii Naturally found as helical chains iii Se not electrically conductive in the dark but quite so in light Group 5A Nitrogen family These 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 b c d e Nearly all compounds are covalent Nitrogen and phosphorus are nonmetals but nitrogen can form N3 anion As and Sb are metalloids Metallic Bi forms mostly covalent compounds but does form Bi3 Nitrogen and Dinitrogen i 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 molecule iv Plants require large amounts of N can t use N2 v Large oxidation state range 3 5 f Ammonia NH3 i Has oxidation state 3 ii One of most common N compounds iii Colorless gas with strong odor acutely toxic iv Liquid polar with strong H bonding g Hydrazine H2N NH2 i Sp3 hybridized ii Long N N bond iii Colorless liquid toxic iv Good reducing agent and base v Very reactive with O2 and H2O2 h Fritz Haber i Received nobel prize in chemistry for NH3 synthesis ii Use catalysts high P and high T iii Enabled Germany to persevere in WWI by providing a source of nitrates for explosives i Dinitrogen fixation i Plants need N but can t fix N2 into usable form can convert N2 to NH4 j Nitrogen oxides i Most important 1 Nitrous oxide N2O a Colorless gas laughing gas sweet smell and taste 2 Nitric oxide NO a Colorless important in biological signaling 3 Nitrogen dioxide NO2 a Toxic yellow brown nasty odor smog component k Phosphorus allotropes l Compounds of phosphorus i Hydrides 1 Phosphine PH3 a Colorless pyrophoric gas very toxic strong reducing agent ii Halides III IV 1 Trihalides PX3 2 Pentahalides 3 Triorganophosphines Group 4A Carbon Family a C nonmetal forms covalent compunds b Metalloids Si and Ge form strong polar covalent bonds c Metallic Sn and Pb exhibit 2 and 4 oxidation states d Allotropes of carbon i Graphite diamond fullerenes nanotubes e Buckyball i In 1996 received nobel prize for discovery of fullerenes C60 looks like soccer ball f Carbides i Carbon combines with metals to form ionic carbides ii C22 C4 are strong bases g Oxides of carbon i CO and CO2 h Carbonic Acid and carbonates i Dissolved CO2 in water is in equilibrium i Cyanide i C and N bound with triple bond isoelectronic with CO very versatile anion very toxic ii Binding strongly and irreversibly to Fe j Silicon in electronics i Wafers k Silicon i Silicon chemistry is quite different from that of C ii Silicon carbide SiC has a diamond like structure iii Silicates make up about 90 of earth s crust iv Simplest silicate has tetrahedral structures l Silicates i Chain double chain sheet and frameworks m Glasses i Glasses have amorphous non crystalline structures broad m p ranges behave like supercooled liquids ii Na2O CaO not resistant to thermal shock windows bottles iii PbO dense high index of refraction n Silicones i Synthetic polymers Group 3A Boron family