Lewis structures of compounds

Although the octet rule and Lewis structures do not present a complete picture of covalent bonding, they do help to explain the bonding scheme in many compounds and account for the properties and reactions of molecules. For this reason, you should practice writing Lewis structures of compounds. The basic steps are as follows ... 

The following examples illustrate the four-step procedure for writing Lewis structures of compounds and an ion. 

A final note about the expanded octet In drawing Lewis structures of compounds containing a central atom from the third period and beyond, sometimes we find that the octet rule is satisfied for all the atoms but there are still valence electrons left to place. In such cases, the extra electrons should be placed as lone pairs on the central atom. Example 9.12 shows this approach. 

Write the Lewis structure of each of the following organic compounds (a) ethanol, Cl IjCLLOH, which is also called ethyl alcohol or grain alcohol (b) methylamine, CH3NH2, a putridsmelling substance formed when flesh decays (c) formic acid, HCOOH, a component of the venom injected by ants. 

Three isomeric alkcnes have the formula C4Hjj (see the following table), (a) Draw Lewis structures of these compounds,... 

A student wrote the formula I IN instead of Nil, on in examination by mistake, (a) Write the name and Lewis structure of the compound corresponding to the formula the student wrote (the N atoms are connected in a chain and the... 

C09-0087. Determine the Lewis structures of the following compounds, and determine which ones have dipole moments. For each molecule that has a dipole moment, draw a ball-and-stick model and include an arrow to indicate the direction of the dipole moment (a) Sip4 (b) H2 S (c) Xep2 (d) GaCl3 and (e) NP3. 

C09-0114. In the lower atmosphere, NO2 participates in a series of reactions in air that is also contaminated with unbumed hydrocarbons. One product of these reactions is peroxyacetyl nitrate (PAN). The skeletal arrangement of the atoms in PAN appears at the right, (a) Complete the Lewis structure of this compound, (b) Determine the shape around each atom marked with an asterisk, (c) Give the approximate values of the bond angles indicated with arrows. 

The lack of secondary Te- -Cl interactions can be correlated with the presence of two aryl substituents with n-donating NMe2 groups. In an opposite way, electron-withdrawing fluorine atoms enhance the Lewis acidity of compounds (RF)2TeX2, leading to fluorine-bridged chains (with X=F) and related chain structures with X=C1 or Br.107... 

Hydrogen never has an octet of electrons in any of its compounds, but rather a pair (or duet, if you prefer). An example is the Lewis structure of H20 (below). In many compounds in which the central atom is from the second period or higher, there are more than eight electrons around the central atom an example of a compound with such an expanded octet is IC13 (below). Finally, in some compounds, there are less than eight electrons around the central atom one such electron deficient compound is BF3. 

Creating the Lewis structures of molecules is a method for determining the sequence of bonding within a molecule and its three-dimensional shape. This works best for covalently bonded molecules, but can also work for ionic compounds. For example, this method can be used to explain why the sequence of bonding in water is H-O-H, rather than H-H-O, and why it has a bent structure, rather than linear. 

Have you ever wondered how to draw the structures of compounds For example, compounds such as CCI4, PBr3 or ions such as SO. To draw the structural formulae we will use the Lewis (electron dot) notation. 

First, write the Lewis structure of each. Figure 10-2 shows the Lewis structures of these compounds. 

Of all the concepts used in chemistry, that of the chemical bond is one of the most useful and, at the same time, one of the most difficult. It is useful because it helps us to understand the structures of compounds and their properties, and it is difficult because it is not easy to relate it to the physical theories, such as quantum mechanics, that underlie chemistry. This is not to say that people have not attempted to find a connection between the chemical bond and quantum mechanics. The Lewis (1923) electron pair model and the orbital overlap model (Coulson 1961) are, perhaps, among the better known attempts, but all are a posteriori rationalizations, trying to explain the properties of the empirical nineteenth-century chemical bond in terms of twentieth-century physical concepts. It is unlikely that, left to themselves, theoretical chemists in the twentieth century would have ever created the idea of a chemical bond had not the concept already been central to the language of structural chemistry. To this day the chemical bond remains largely an empirical concept. 

Trimethylbortme Dih).2 We may assume that the methyl groups will have their usual configuration found in organic compounds. The Lewis structure of (CHj)jB will place six electrons in the valence shell of the boron atom, and in order that the-electron pairs be as fair apart as possible, the methyl groups should be located at the comers of an equilateral triangle. This results in sp2, or trigonal Ur), hybridization for the bcron atom (Fig. 6.1b). 

Exercise 22-27 Using the rationale developed in Section 22-5, predict the major products of nitration of the following compounds. It will help to work out the Lewis structures of the substituent groups. 

Write the Lewis structures of the following organic compounds (a) ethanol, CH3CH2OH, which is also called ethyl alcohol or grain alcohol ... 

A highly toxic gas that has been used in chemical warfare gives the following elemental analysis figures 12.1% carbon, 16.2% oxygen, and 71.7% chlorine by mass. Its molar mass is 98.9 g-moU1. Write the Lewis structure of this compound. 

Write the Lewis structure of each of the following compounds, predict the shape about each central atom, and state whether it is polar or nonpolar (a) S02C12 (S is the central atom) (b) F3SSF (c) AsC15 (d) SiF4. 

Write the Lewis structure of each of the following compounds, predict the shape about each central atom,... 

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