CHEM 1120 1nd Edition Lecture 19 Outline of Last Lecture I. Classes of elementsa. Metalsb. Metalloidsc. NonmetalsII. Properties of NonmetalsIII. Review of Periodic propertiesa. Ionization Energyb. Electron Affinityc. Electronegativity d. Atomic Radiie. Periodic TrendsIV. Group 1A – Hydrogena. 3 isotopesb. 3 types of hydrogen chemistryc. Properties of hydrogend. Hydrogen productionV. Noble Gases – Group 8Aa. Least reactive groupOutline of Current Lecture I. Halogensa. Reactive Non-metalsb. Propertiesc. Preparationd. Important compoundse. UsesII. Group 6A – Oxygen Familya. Allotropes of Oxygenb. Oxidesc. Superoxidesd. SulfurCurrent LectureI. HalogensThese 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. Halogens have out electron configurations ns2np5b. They have large electron affinities and ionization energiesc. They tend to accept on electron to form anionsd. Reactive Non-metalsi. Monoanions are halides (X-)ii. A standard state, F2 and Cl2 are yellowish gases, Br2 is a red-brown liquid,and I2 is a red-purple solid with high vapor pressureiii. F-smal,l reactive, high electronegativity, strong oxidizing agentiv. Cl-abundant, biologically important, strong oxidizing elementv. I-least reactive and toxic of halogens, weaker oxidizing agent, biological trace elementvi. At-radioactivee. Propertiesi. Very reactive: good oxidizers, react with nearly all metals and non-metals,can oxidize anions of halides below them on the periodic chartii. Properties of fluorine are unique: reacts explosively with most elements, oxidizes wateriii. Bigger the element, bigger the bond length, bump in bond energy near Cl,decreasesf. Preparation of Halogensi. Prepared from halidesii. Electronegative F2, Cl2 must be prepared by electrolysisiii. Fluorine cannot be prepared by aqueous electrolysis-water is more easily oxidized, F2 is prepared by the electrolysis of HFiv. Chlorine prepared by electrolysis to give Cl2 and Na or Cl2, H2, and NaOHv. Bromine and iodine prepared from seawater by oxidation with Cl2g. All halogens have a -1 oxidation stateh. Important compoundsi. Metal halides: CaCl2ii. Oxides, oxoacids, and salts: ClO2, HBrO3, KIO3iii. Hydrogen halides: HCliv. Interhalogen compounds: BrF5v. HX are acidic, acid strength increases down the seriesvi. HF is very reactive, other HX less soi. Uses for halogensi. Chlorine: most important industriallyii. Bromine: photographic film, not an essential element for lifeiii. Cl/Br: used to make non-flammable clothingiv. Iodine: antiseptic II. Group 6A – Oxygen Familya. Group members exhibit covalent and ionic behaviorsb. Oxygen and Sulfur are nonmetalsi. Both form many covalent compoundsii. Oxygen forms many ionic compounds, sulfur forms fewer ionic compoundsc. Se and Te are metalloidsd. Po: radioactive metale. Allotropes of oxygen-O2 and O3i. O2 used for respiration, oxidant, in acids, prepared by fractional distillation of liquefied airii. Ozone (O3): less stable than O2, toxic, bent diamagnetic molecule, used to purify water, generated by lightning, decomposes to O2 and O upon absorbing UV photonsf. Sulfuri. More than 10 allotropes, most stable consisting of S8 rightsg. Seleniumi. Se8 ringsh. Oxidesi. Oxygen is the second most electronegative elementii. Always has a negative oxidation state, except when bound to Fiii. Acidic oxides like SO2 and SO3 form acids when exposed to wateriv. Basic oxides like BaO form a hydroxide ion when they react with waterv. Covalency1. Alkali metal, alkaline earth oxides are ionic2. Oxides of the metals and metalloids are ionic in low oxidation states and polar covalent in high oxidation states3. Oxides of the non-metals are polar covalentvi. Basicity1. Decreases from left to right, increases down rowsvii. Melting point1. Metallic oxides have high melting points2. Oxides of non-metals are liquids or gases at ambient Tviii. Hydrogen Peroxide (HOOH)1. Polar reactive molecule that disproportionates to H2O and O2 in presence of heat, light, some metals2. Antiseptic: oxidizes organic matteri. Superoxidesi. Most active metals form superoxides through reaction with O2ii. React with H2O to form O2iii. Peroxide and superoxide are metabolic byproducts that can do indiscriminate biological damageiv. Enzymes catalase, superoxide dismutase, and peroxidase convert O2 into H2O and O2j. Sulfuri. Brittle, soft yellow solid with low mp that facilitates its melting in rock with hot steam and transport to surface as emulsionii. Large oxidation number range (-2 to +6)iii. Use in gunpowder iv. Organic compounds of sulfur1. Compounds with SH groups are called thiols2. Smell badv. Inorganic sulfides1. Found in some protein active sites2. Pyrites contain the disulfide ion3. Minerals like galena and cinnabarvi. Compounds of sulfur1. Disulfides are important structural feature in proteins, “staple” proteins together vii. Sulfuric Acid1. Versatile diprotic acid2. Strong oxidizing agent and strong acid3. #1 chemical from dissolution 4. “Concentrated” =