Chapter 1-Organic Chemistry

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It takes about formal charges,hybridization and Lewis structure mainly! among other stuff.


<ul><li><p>*Organic Chemistry</p><p>Organic Chemistry: </p><p>Originally defined as study of compounds from living things / organisms (compounds from nature).Later, chemists made (synthesized) compounds in the laboratory</p><p>NOW: Organic chemistry is the study of compounds containing carbon.</p><p>However,Biochemistry is the study of the chemicals and processes that sustain life (the life on Earth that is based on carbon compounds).</p><p>Biochemistry is based on and overlapped with Organic Chemistry.</p></li><li><p>Organic Chemistry*Over 10 million organic compounds have been identifiedabout 1000 new ones are discovered or synthesized and identified each day!Unlimited number of organic compounds are possibleWhy?C is a small atom it forms single, double, and triple bondsit is intermediate in electronegativity (2.5)it forms strong bonds with C, H, O, N, and some metals.</p></li><li><p>*Chapter 1. Bonding and Isomerism1.1 The Review of Atomic StructureAtomelectron(s)Atomic weight = no. of proton(s) + no. of neutron(s)Electrons are located in orbitalspossibility of electrons around the nucleus</p></li><li><p>Quantum Numbers*n - principal quantum number, n = 1, 2, 3, 4, </p><p> l - azimuthal (angular momentum) quantum number, l &lt; n (1, , n - 1)</p><p>ml - magnetic quantum number, total ml values = 2l + 1 (-l,, 0, , l)</p><p>ms electron spin quantum number, ms values = +, or -. </p><p>One orbital can only hold up to two electrons (Pauli Exclusion Principle).</p><p>Orbitals are grouped in electron shells (based on n values).</p><p>Different orbitals have different shapes (based on l values). e.g. s sphere, l= 0; p dumbbell, l= 1. </p></li><li><p>*Table 1.1 Numbers of orbitals and electrons in the first three shells</p></li><li><p>*Shapes of Atomic OrbitalsA p- orbital consists of two lobes arranged in a straight line with the center at the nucleus.All s orbitals have the shape of a sphere, with its center at the nucleus. Of the s orbitals, 1s is the smallest, 2s is larger, and a 3s is even larger, etc.</p></li><li><p>*Aufbau principle for filling electrons on atomic orbitals</p></li><li><p>*</p><p>Type of OrbitalsNo. of OrbitalsNo. of Electronss (l=0)1 =(2 x 0+1)2p (l=1)3 =(2 x 1+1)6d (l=2)5 =(2 x 2+1)10f (l=3)7 =(2 x 3+1)14</p><p>Shell Number Max. No. of Electrons on the shellOrbitals (No.)12 (2 x 12)1s (1)28 (2 x 22)2s 2p (4)318 (2 x 32)3s 3p 3d (9)432 (2 x 42)4s 4p 4d 4f (16)</p></li><li><p>*</p></li><li><p>*Figure 1.1 Sodium chloride is an ionic crystal</p></li><li><p>*Table 1.4 Electronegativities of some common elements</p></li><li><p>*</p></li><li><p>*Figure 1.3 The molecular orbital representation of covalent bond formation</p></li><li><p>*Figure 1.4 Orbital overlap to form s bonds</p></li><li><p>*Chapter 1, Page 29 p+p = bond</p></li><li><p>*</p></li><li><p>*</p></li><li><p>*Resonance StructuresResonance is the use of two or more Lewis structures that differ only in the distribution of the valence electrons in representing the bonding in a species. The skeleton structure does not change; only the placement of bonds is different. We indicate resonance structures with a double-headed arrow.e.g. the Lewis structure of CO32-</p><p>Calculate the formal charges of C and O atoms in CO32-FC (C) = 4 4 0 = 0 FC (O*) = 6 2 4 = 0 FC(O) = 6 1 6 = -1 </p><p>These Lewis structures ------ resonance structuresThe real molecule or ion is described by an average of these resonance structures.</p><p>Benzene, C6H6</p><p>*</p></li><li><p>*1.5 Symbols used in Organic Chemistry</p><p>(1) Curved arrowscurved arrow --- used for transferring a pair of electrons</p><p>fishhook or half-headed curved arrow --- used for transferring one electron</p><p>(2) Straight arrowsstraight arrow --- used for pointing from reactants to products in a chemical equation double headed straight arrow --- used for converting resonance structures half headed straight arrow --- used for a reversible chemical reaction or an equilibrium1.6 Hybridization and / bonds (Review)Linus Pauling proposed the theory of orbital hybridization.(a) Hybrid orbitals can be formed by mixing s, p and / or d orbitals on an atom in order to form bonds in the molecules.(b) Hybrid orbitals have an orientation in space that matches the geometry of a molecule.(c) The number of hybrid orbitals formed is the same as the number of atomic orbitals used for the hybridization.</p></li><li><p>*</p></li><li><p>*</p></li><li><p>*</p></li><li><p>*</p></li><li><p>*</p></li><li><p>*Table 1.6 The main functional groups</p></li><li><p>*</p></li><li><p>*(c) Functional Groups Containing both Oxygen and Nitrogen (CO)NH2--- amide (primary)(d) Functional Groups Containing SulfurSH--- thiol (also mercaptane) CSC ---- thioether (also disulfide)</p></li><li><p>*Figure 1.11 Examples of natural acyclic compounds</p></li><li><p>*Figure 1.12 Examples of natural carbocyclic compunds with rings of various sizes and shapes </p></li><li><p>*Figure 1.13 Examples of natural heterocyclic compounds</p></li></ul>