PowerPoint PresentationSlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Halogens (elemental forms)Slide 13Slide 14Slide 15Organize Elements by Stable Oxides, Hydrides, HalidesSlide 17Slide 18Modern basis for the periodic table: the number of protons in the atomic nucleus (atomic number)Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Slide 451Lecture 4: C1403 Monday, September 19, 2005Stoichiometry : Mass relationships involved in compositions of compounds and in balanced chemical equations.Converting mass of substances to moles (numbers of atoms and molecules) and moles to mass.2From the mass of 22.4 L of gases to atomic and molecular molar masses.22.4 L determined as containing a mole of a gas.Compound (22.4 L) Mass % of O Mass of OWater 18 g 89% O 16 g O/moleCarbon dioxide 44 g 73% O 32 g O/moleSulfur trioxide 80 g 60% O 48 g O/moleOxygen 32 g 100% O 32 g O/moleData consistent with atomic molar mass of H = 1 & O = 16.Creation of a ranking of atomic masses through Avogadro’s hypothesis and the mass of volumes of gases.3Mole equivalents:2 H2 = 1 O2 = 2 H2OAtom equivalents:4 H + 2 O = 4 H + 2 OMass to mole to mole to mass conversion4 g H2 = 2 mol H2 = 1 mol O2 = 32 g O24 g H2 = 2 mol H2 = 2 mol H2O = 36 g H2OEquation: 2 H2 + O2 = 2 H2O (constitutional structure)Molecular compositionsBalanced equations4Laboratory amounts: massesChemical amounts: numbers of atoms or molecules. Equal amounts means equal numbers of atoms5Equal masses: excess of lighter atom in reaction A + B = ABA is limiting reactantEqual number:No excess of either A or B in reactionA + B = ABA BLimiting reactant depends on number not on mass.6Chapter 3 Chemical Periodicity and the Formation of Simple Compounds. Lewis structures of molecules. Learning goals:Periodic Table(3.1) The characteristics of groups of the 8 representative groups (I-VIII) of elements.(3.2) The relationships among the elements in the columns and rows of the Periodic Table.(3.2) Periodic Properties. Electronegativity.Lewis structures(3.3) Lewis dot electronic structures of atoms.(3.4, 3.5) Lewis dot-line constitutional structures of molecules. How atoms are connected.(3.7) Predicting the dipole moments and the configuration (3D) structure of molecules from Lewis structures.7(3.2) The Periodic TableClassical example of the building of a paradigm: Repeated patterns of similarity in the composition of binary compounds triggered a search for order and organization of the elements in terms of observable properties.First organization of the periodic: By atomic mass.Periodicity of properties appeared as an arrangement by mass.About 1870 Mendeleev (Russia) and Meyer (Germany) proposed the initial forms of the periodic table.Mendeleev dared to propose that deviations from periodicity were due to either incorrect atomic weights or undiscovered elements. He predicted the properties of six undiscovered elements. Mendeleev’s paradigm wins (for a while)!8(3.1) Groups of Elements in the Periodic TableEight Groups (the 7 groups of representative elements and the group of noble gases):I. Alkali metals: (H), Li, Na, K, Rb, CsII. Alkali earth metals: Be, Al, Ca, Sr, Ba, RaIII. Boron family: B, Al, Ga, In, TlIV. Carbon family: C, Si, Ge, Sn, PbV. Nitrogen family: N, P, As, Sb, BiVI. Chalcogens O, S, Se, Te, PoVII. Halogens F, Cl, Br, I, AtVIII.Noble gases: (He), Ne, Ar, Kr, Xe, Rn Representative metals (I and II) and non-metals (VI and VII).9Group I (The alkali metals): Li, Na, K, Rb, Cs10Most of the elements in the periodic table are metals11Group VI (The chalcogens): O (oxygen), S (sulfur), Ge (germanium), Sn (tin)12Halogens (elemental forms)Group VII (The halogens): F (not shown), Cl (gas), Br (liquid), I (solid)13Br2 (non-metal)+ Al (metal) Al2Br6 (AlBr3)What is the basis of chemical reactivity?14. Grouping elements by similarities. Science is an exercise in collecting data, detecting similarities in the data and in determining the source of the similarities at an atomic (microscopic) level.Many elements form binary compounds with H. Since H is the “simplest” element (smallest atomic mass), it is natural to consider the properties of the compounds formed between elements, X, and H. These binary compounds, XHn, are called hydrides. Exemplars: CH4, NH3, OH2, FH (XHn n = 4, 3, 2, 1, respectively)Group binary hydrides of that bind the same number of H.Examples of grouping of hydrides of elements: n = 4 CH4, SiH4, GeH4n = 3 NH3, PH3, AsH3n = 2 OH2, SH2, SeH2n = 1 FH, ClH. BrH15Clear cut grouping of metals (Groups I and II) forming binary compounds with non-metals (Groups VI and VII)Alkali metals, X: Li, Na, K, Rb, CsX2O Li2O, Na2O, K2O, Rb2O, Cs2OXCl LiCl, NaCl, KCl, RbCl, CsClAlkali earth metals, X: Be, Mg, Ca, Sr, BaXO BeO, MgO, CaO, SrO, BaOXCl2BeCl2, MgCl2, CaCl2, SrCl2, BaCl2 Chalcogens, X: O, S, Se, TeNa2X Na2O, Na2S, Na2Se, Na2TeCaX CaO, CaS, CaSe, CaTeHalogens, X: F, Cl, Br, ILiX LiF, LiCl, LiBr, LiICaX2CaF2, CaCl2, CaBr2, CaI216Organize Elements by Stable Oxides, Hydrides, HalidesLi2OLiClBeOBeCl2B2O3BCl3CO2CCl4NONCl3[O]H2OF-HFNeNa2ONaClMgOMgCl2Al2O3AlCl3SiO2SiCl4POPCl3SO42-H2SCl-HClArK2OKClCaOCaCl2Ga2O3GaCl3GeO2GeCl4AsOAsCl3SeO42-H2SeBr -HBrKrRb2ORbClSrOSrCl2In2O3InCl3SnO2SnCl4SbOSbCl3TeO42-H2TeI-HIXe I II III IV V VI VII VIII17(3.2) The Periodic Table(1) The elements can be arranged in groups (columns) of elements that possess related chemical and physical properties.(2) The elements can be arranged in periods (rows) of elements that possess progressively different physical and chemical properties.(3) Original Paradigm: The chemical and physical properties of the element are periodic functions of their atomic masses.(4) Modern Paradigm: The chemical and physical properties of the elements are periodic functions of the atomic number (number of protons in the nucleus = number of electrons in the neutral atom).18Dmitri MendeleevOrganization of the elements by relative atomic mass and periodic properties.19Modern basis for the periodic table: the number of protons in the atomic nucleus (atomic number)198Au20An alphabetical arrangement of the elements (information)21A spiral periodic table22Same information (atomic numbers and atomic masses), provided with a constitutional (connected) structure = knowledge (connecting properties and