【正文】 gous series are called homologs. Propane (CH3CH2CH3) and butane (CH3CH2CH2CH3) are homologs. StructureConstitutional IsomerismConstitutional isomers: pounds with the same molecular formula but a different connectivity of their atomsexample: C4H10 Nomenclature of Alkyl SubstituentsRemoving a hydrogen from an alkane results in an alkyl substituent (or an alkyl group).Alkyl substituents are named by replacing the “ane” ending of the alkane with “yl.” The letter “R” is used to indicate any alkyl group.Primary (1176。 H: a hydrogen bonded to a 3176。CThe reason of the relative rates of radical formation:By paring the values for the sum of the two propagating steps for the monohalogenation of methane, we can understand why alkanes undergo chlorination and bromination but not iodination and why fluorination is too violent a reaction to be useful.Chapter 3 Alkene Structure and nomenclatureSaturated hydrocarbons:. alkanes contain the maximum number of carbon–hydrogen bonds possible—that is, they are saturated with hydrogen.Unsaturated hydrocarbon: contains one or more carboncarbon double or triple bondsAlkene: contains a carboncarbon double bond and has the general formula CnH2n.Degree of unsaturation (or Index of hydrogen deficiency) :. The total number of πbonds and rings in an alkene is called its degree of unsaturation.Notes:the molecular formula of the reference hydrocarbon is CnH2n+2for each atom of a Group 7 element (F, Cl, Br, I), add one Hno correction is necessary for the addition of atoms of Group 6 elements (O,S) to the reference hydrocarbonfor each atom of a Group 5 element (N, P), subtract one hydrogenA double bond consists of one sigma bond formed by the overlap of sp2 hybrid orbitals and one pi bond formed by the overlap of parallel 2p orbitalsthe two carbon atoms of a double bond and the four atoms bonded to them lie in a plane, with bond angles of approximately 120176。 a reaction in which heat is releasedendothermic reaction: a reaction in which the enthalpy of the products is higher than that of the reactants。torsional strain: there are 6 sets of eclipsed hydrogen interactionsstrain energy is about 116 kJ ( kcal)/mol Cyclobutanepuckering from planar cyclobutane reduces torsional strain but increases angle strainthe conformation of minimum energy is a puckered “butterfly” conformationstrain energy is about 110 kJ ( kcal)/mol Cyclopentanepuckering from planar cyclopentane reduces torsional strain, but increases angle stainthe conformation of minimum energy is a puckered “envelope” conformationstrain energy is about 42 kJ ( kcal)/mol CyclohexaneChair conformation: the most stable puckered conformation of a cyclohexane ringall bond CCC bond angles are 176。 carbonTertiary (3176。 the position of all nuclei must be the same4. have the same number of paired and unpaired electronsfilled valence shellsstructures in which all atoms have filled valence shells contribute more than those with one or more unfilled valence shellsstructures that carry a negative charge on the more electronegative atom contribute more than those with the negative charge on the less electronegative atom Molecular Orbital TheorySigma 1s bonding and antibonding MOsMO energy diagram for H2: (a) ground state and (b) lowest excited statepi bonding and antibonding MOs Hybrid OrbitalsHybridization of orbitals (L. Pauling)the bination of two or more atomic orbitals forms a new set of atomic orbitals, called hybrid orbitalsWe deal with three types of hybrid orbitalssp3 (one s orbital + three p orbitals)sp2 (one s orbital + two p orbitals)sp (one s orbital + one p orbital)Overlap of hybrid orbitals can form two types of bonds depending on the geometry of overlaps bonds are formed by “direct” overlapp bonds are formed by “parallel” overlapeach sp3 hybrid orbital has two lobes of unequal sizethe sign of the wave function is positive in one lobe, negative in the other, and zero at the nucleusthe four sp3 hybrid orbitals are directed toward the corners of a regular tetrahedron at angles of 176?！队袡C(jī)化學(xué)》課程講義（適用于化學(xué)教育、應(yīng)用化學(xué)、化學(xué)工程專業(yè)）溫梅姣 編寫教 化學(xué)與資源環(huán)境學(xué)院二〇一〇年七月1Organic ChemistryContentsChapter 1 Introduction………………………………………………………………1 The development of Organic Chemistry as a science………………………1 The importance of Organic Chemistry………………………………………1 How to study Organic Chemistry……………………………………………2 Covalent Bonding amp。 these bonds are called polar covalent bonds Formation of IonsA rough guideline: ions will form if the difference in electronegativity between interacting atoms is or greaterexample: sodium (EN ) and fluorine (EN )we use a singleheaded (barbed) curved arrow to show the transfer of one electron from Na to Fin forming Na+F, the single 3s electron from Na is transferred to the partially filled valence shell of F Polar and Nonpolar MoleculesTo determine if a molecule is polar, we need to determine if the molecule has polar bondsthe arrangement of these bonds in spaceMolecular dipole moment (m): the vector sum of the individual bond dipole moments in a moleculereported in debyes (D)these molecules have polar bonds, but each has a zero dipole momentthese molecules have polar bonds and are polar moleculesformaldehyde has polar bonds and is a polar molecule ResonanceFor many molecules and ions, no single Lewis structure provides a truly accurate representationLinus Pauling 1930smany molecules and ions are best described by writing two or more Lewis structuresindividual Lewis structures are called contributing structuresconnect individual contributing structures by doubleheaded (resonance) arrowsthe molecule or ion is a hybrid of th