Formulas, condensed Lewis

Several kinds of formulas are used by organic chemists to represent organic compounds. Some of these formulas involve a shorthand notation that requires some explanation. Structural formulas actually show which atoms are bonded to which. There are two types of structural formulas, complete Lewis structures and condensed structural formulas. In addition, there are several ways of drawing condensed structural formulas. As we have seen, a Lewis structure symbolizes a bonding pair of electrons as a pair of dots or as a dash (—). Lone pairs of electrons are shown as pairs of dots. 

Draw the dash formulae, condensed formulae and Lewis structures of ... 

Convert the following condensed formulas into Lewis structures. 

Fischer projection, 71 Ruorine, role in nmr, 243 Formal charge, 7 Formic acid, 331 Formulas, condensed, 2 Lewis, 2... 

Plan To determine the condensed structural formula of the product, we must first write the condensed structural formula or Lewis structure of the reactant In the hydrogenation of the alkene, H2 adds to the double hond, producing an alkane. 

You should be able to draw chemical formulas that show all of the valence electrons in a molecule (Lewis structures), using lines for bonds and dots to show unshared electrons. You should be proficient in representing structures as dash structural formulas, condensed structural formulas, and bond-line structural formulas. In particular, the more quickly you become skilled at using and interpreting bondline formulas, the faster you will be able to process structural information in organic chemistry. You have also learned about resonance structures, the use of which wiU help us in understanding a variety of concepts in later chapters. 

Structural formula, structural diagram, line formula, condensed formula, Lewis diagram... 

C21-0053. Three phosphate anions can condense to form a ring whose chemical formula Is P3 Og. Determine the Lewis structure and draw a ball-and-stick model of this anion. 

Molecular formulas merely include the kinds of atoms and the number of each in a molecule (as C4H , for butane). Structural formulas show the arrangement of atoms in a molecule (see Fig. 1-1). When unshared electrons are included, the latter are called Lewis (electron-dot) structures [see Fig. 1-1(/)]. Covalences of the common elements—the numbers of covalent bonds they usually form—are given in Table 1-1 these help us to write Lewis structures. Multicovalent elements such as C, O. and N may have multiple bonds, as shown in Table 1-2. In condensed structural formulas all H s and branched groups are written immediately after the C atom to which they are attached. Thus the condensed formula for isobutane [Fig. l-l(f>)) is CH,CH(CH,)... 

Q Draw and interpret Lewis, condensed, and line-angle structural formulas. Calculate formal charges. 

A complete structural formula (such as a Lewis structure) shows all the atoms and bonds in the molecule. A condensed structural formula shows each central atom along with the atoms bonded to it. A line-angle formula (sometimes called a skeletal structure or stick figure)... 

Condensed formulas are often confusing, especially when they involve carbonyl groups. Whenever you see a complicated condensed formula, convert it to a Lewis structure first for clarity. 

Compound Lewis Structure Condensed Structural Formula... 

When a condensed structural formula is written for a compound containing double or triple bonds, the multiple bonds are often drawn as they would be in a Lewis structure. Table 1-3 shows examples of condensed structural formulas containing multiple bonds. Notice that the —CHO group of an aldehyde and the —COOH group of a carboxylic acid are actually bonded differently from what the condensed notation suggests. Condensed structures are assumed to follow the octet rule even if the condensed notation does not show the bonding. 

As you can see from Tables 1-2 and 1-3, the distinction between a complete Lewis structural formula and a condensed structural formula can be blurry. Chemists often draw formulas with some parts condensed and other parts completely drawn out. You should work with these different types of formulas so that you understand what all of them mean. 

Draw complete Lewis structures for the following condensed structural formulas, (a) CH3(CH2)3CH(CH3)2 (b) (CH3)2CHCH2C1... 

Ssmple Problem 1.7 convert each condensed formula to a Lewis structure. 

Figure 21-2 Representations of a molecule of methane, CH4. (a) The condensed and Lewis formulas for methane, (b) The overlap of the four sp carbon orbitals with the s orbitals of four hydrogen atoms forms a tetrahedral molecule, (c) A ball-and-stick model, (d) a space-filling model of methane, and (e) a three-dimensional representation that uses the wedged line to indicate a bond coming forward and a dashed line to represent a bond projecting backward.

Figure 27-3 Models of ethane, C2Hg. (a) The condensed and Lewis formulas for ethane, (b) A ball-and-stick model, (c) a space-filling model of ethane, and (d) a 3-D representation.

Study Figures 17.1, 17.2, and 17.3 and then practice converting Lewis structures into condensed formulas and line drawings, and vice versa. 

Write condensed formulas to represent the Lewis structures in parts a through 1 of Exercise 17.1. 

Given a Lewis structure of an organic molecule, draw its condensed formula and line drawing. 

Given a Lewis structure, a condensed formula, or a line drawing for an organic compound, identify it as representing an alkane, alkene, alkyne, arene (aromatic), alcohol, carboxylic acid, ether, aldehyde, ketone, ester, amine, or amide. 

Write condensed chemical formulas to represent the Lewis structures in parts (a) through (j) of problem 52. (For example, 2-propanol can he described as CH3CH(0H)CH3.)... 

Use condensed electron configurations and Lewis electron-dot symbols to depict the monatomic ions formed from each of the following atoms, and predict the formula of the compound the ions produce ... 

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