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Download Group 14 Elements (The Tetrels) Characteristics General Trends
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Group 14 Elements (The Tetrels) Characteristics Solid at room temperature Nonmetals, Metalloids, Metals Like to form tetrahedral compounds Semiconductors Oxidation state: +4 Pb shows inert pair effect w/ +2 since the two p electrons are lost, leaving a relatively inert valence s2 orbital General Trends Ionization Energy (kJ mol-1) Electron Affinity (kJ mol-1) ElectroElectronegativity Covalent Radius (A) Bond Energy (kJ mol-1) X-X Bond Energy (kJ mol-1) X-H C 1086 122 2.54 0.77 356 416 Si 786 134 1.92 1.17 210210-250 323 Ge 762 120 1.99 1.22 190190-210 280 Sn 709 120 1.82 1.40 105105-145 252 Pb 716 35 1.85 1.44 Element * The electronegativity of hydrogen is 2.30. Highlights of Carbon Chemistry Carbon is not only a “first row anomaly,” anomaly,” but also an anomaly in the entire periodic table! Basic Physical Properties: Average molecular weight: 12.011 amu Four valence electrons, ability to bind to four different “things” things” in a tetrahedral geometry Exists as graphite, coal and diamond elementally Diamond Forms covalent bonds since its EN is 2.5 Coal Graphite 1 What makes carbon so special? Can form stable double and triple bonds with itself (catenation) (catenation) and other species Ability to form four bonds allows carbon to make complex structures structures Shorter chemical bonds = more stability Can be found in all oxidation states unique to its family ((-4 to +4) Complex organic compounds, simple inorganic compounds Forms two common gaseous oxides (CO2 and CO) Carbofuran The Other Elements in Group 14 Longer chemical bonds, no π bonding (Si and Ge compounds with π bonds very unstable) Weaker, longer bonds result in higher reactivity in general Form only solid networknetwork-covalent or ionic oxides Oxidation states are limited to +4 or +2 (Si (Si can be found in –4 or +4 state), further down the table +2 becomes more common -Carbon can be found in a menagerie of products, including black paint, explosives, certain cathode ray tubes, rubber tires, typewriter ribbons, phonograph records, carbonated beverages and fuels (hydrocarbons). Biological -Carbon is essential to human life as we know it -Nearly every molecule in living organisms contain carbon -Carbon dioxide is essential in the gaseous exchange necessary to aerobic organisms -waste product for humans, necessary resource for plant life -Most pharmaceuticals today are developed around carbon -easily received by the organic human body The MANY Uses of Carbon -Carbon is one of the planet’ planet’s most useful elements, largely because it can easily form a variety of CC-C chains or rings Industrial -Carbon plays many important roles in industrial processes -Diamonds, apart from being beautiful, are one of the hardest substances on earth. They are therefore used to cut other hard substances, such as glass -Graphite, apart from being found in pencils, is used as an industrial machine lubricant -Graphite can also refract light, making it ideal for use in highhigh-heat areas, such as the insides of ovens Industrial Uses for Si, Ge, and Sn SilicaSilica- glass GermaniumGermanium- construction of transistors TinTin- plate steel for tin cans, windows, and solder alloys 2 Uses of Lead By far the most common use of lead worldwide is for the leadlead-acid battery. Lead is highly conductive and resistant to corrosion. LeadLead-antimony alloy grids. Types of Lead-Acid Batteries SLI (starting, lighting, and ignition) leadlead-acid battery Traction battery Stationary battery Chemistry of Lead-Acid Battery Grids Pb (s) + SO4-2 (aq) aq) Æ PbSO4 + 2e PbO2 + SO4- (aq) aq) + 4H+ + 2e- Æ PbSO4 + 2H2O Pb (s) + PbO2 + 2SO 2SO4-2 (aq) aq) + 4H+ Æ 2PbSO4 + 2H2O References Atkins, P.; Overton, T.; Rourke, Rourke, J.; Weller, M.; Armstrong, F. Inorganic Chemistry; Chemistry; 4th Edition; W. H. Freeman and Company: New York, NY, 2006. Chemical Elements; Carbon, Thomson Learning, Inc.: Lawrenceville, NJ, 20052005-2006. Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change; Change; 3rd Edition; McGraw Hill Publishing Inc: New York, NY, 2003. Lead Products and Their Uses; LeadLead-acid batteries. Lead Development Association International: London; http://www.ldaint.org/technotes4.htm. http://www.ldaint.org/technotes4.htm. Accessed 9April 2007. 3
