CHEM 211 Lecture Notes - Lecture 2: Lewis Structure, Chemical Formula, Heteroatom
8 Sep 2016
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Different models: ball-and-stick model, electron-dot formula/lewis structure, dash formula, condensed formula, and bond-line formula. Bond-line formulas: each line represents a bond, each bend in a line (=terminus) = carbon. Don"t write out the hydrogens: unless the h is on a heteroatom (=an atom that"s not carbon), write all non carbon/hydrogen atoms, double bonds = two lines, triple = three lines. Anything in parentheses is attached to the carbon before it, in a molecular formula. Dashed wedges = projects behind the plane of the paper. Solid wedge = projects out of the plane of the paper. Normal line = on the plane of the paper: there can be three-dimensional bond-line formulas too. Resonance structures = alternate lewis dot structures: start with a lewis dot structure, only electrons (lone pair and bonds) can be moved around for resonance. Never move atoms. that is a chemical reaction: hybrid= the average of all of the resonance structures.
