The Halogens and Noble Gases: Their Properties and Uses in Chemistry, Study notes of Chemistry

Download The Halogens and Noble Gases: Their Properties and Uses in Chemistry and more Study notes Chemistry in PDF only on Docsity! 1 Chapter 19. The Representative Elements: Groups 5A Through 8A 19.1 The Group 5A Elements 19.2 The Chemistry of Nitrogen 19.3 The Chemistry of Phosphorus 19.4 The Group 6A Elements 19.5 The Chemistry of Oxygen 19.6 The Chemistry of Sulfur 19.7 The Group 7A Elements 19.8 The Group 8A Elements Crystals of rhombic sulfur Figure 18.1: The periodic table. 2 Figure 12.39: Special names for groups in the periodic table Figure 12.39: Special names for groups in the periodic table (cont’d) 5 Oxyacids and Oxyanions of the Halogens • HOCl, hypochlorous acid, hypochlorite ion (OCl-) HOClO, chlorous acid, chlorite ion (ClO2-) HOClO2, chloric acid, chlorate ion (ClO3-) HOClO3, perchloric acid, perchlorate ion (ClO4-) ← See Fig. 19.25 Oxychloroanions • Many of the oxyacids and corresponding salts are powerful oxidizing agents that can react explosively. Handle with care!! • Cl2 (aq) + H2O (l) HOCl (aq) + H+ (aq) + Cl- (aq) 0 cold water +1 -1 Cl2 is both oxidized and reduced in this reaction (i.e. A disproportionation reaction). Note that only one small oxyacid is formed by F increasing strength of acid with # of oxygen atoms attached to the halogen Figure 19.25: Structures of the oxychloro anions. 6 Other Halogen Compounds interhalogen compounds Figure 19.26: Idealized structures of the interhalogens CIF3 and IF5. 7 AgX, silver halides used in photography Compounds with Carbon: monomers and polymers C C F FF F n polymerization C C F F F F n poly(tetrafluoroethylene) Teflon – nonstick coating in cookware, etc.tetrafluoroethylene C C H ClH H n polymerization C C H Cl H H n vinyl chloride poly(vinyl chloride) PVC • water pipes and tubing in homes Some Applications of Halogen Compounds 19.8 The Group 8A Elements: The Noble Gases • Relatively unreactive because of their complete valence shells. – He, Ne, and Ar have known compounds – Kr and Xe form stable chemical compounds Xe (g) + 2 F2 (g) XeF4 (s) • The geometry of XeF6 is not octahedral 7 electron pairs around Xe 8A He Ne Ar Kr Xe Rn can form stable compounds Radon, radioactive 2s2 for He ns2np6 (others) valence electron configuration X e F F F FF F 400℃ 6 atm