Learn about Bonds

Thanks to the great advances in technology, you can learn about and research bonds for the very best price the Internet offers free. 

In general terms, the Internet has revolutionized the way we invest, but more important, it has opened up investing to a group of people who previously solely relied on a broker or advice from a relative, colleague, or neighbor. With a few clicks, anyone can learn about securities. And once you find out what to buy, you can click the mouse a few more times and enter into a transaction—the seamless combination of information and commerce. 

But some feel that the best information should not be free, namely, the online brokerages. As such, these transaction providers have substantial content on their sites that seeks to educate investors, but beware Their goal is to have you open an account (i.e., buy or sell). As any investment advisor would tell you, you should not buy or sell until you have read everything you possibly can about the security under consideration. 

There are three categories to consider when searching the Web for bond information (l) nonprofit organizations, (2) online media and news sites, and (3) online brokerages. 

The Investor Information page (http //www.sec.gov) contains general, straightforward information on subjects relevant to the individual investor who is committed to investing online. The bond information is not as strong as that for stocks. 

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We have learned about bond orbitals which represent chemical bonds. In this section, we learn how interactions of bonds determine molecular properties. Interactions of bond orbitals give molecular orbitals, which show behaviors of the electrons in molecules. 

In previous chapters, you learned that elements within a group on the periodic table have similar properties. Many of these properties depend on the number of valence electrons the atom has. These valence electrons are involved in the formation of chemical bonds between two atoms. A chemical bond is the force that holds two atoms together. Chemical bonds can form by the attraction between the positive nucleus of one atom and the negative electrons of another atom, or by the attraction between positive ions and negative ions. This chapter discusses chemical bonds formed by ions, atoms that have acquired a positive or negative charge. In Chapter 8, you will learn about bonds that form from the sharing of electrons. 

A collection of the basic building block, a lamina, was bonded together to form a laminate in Chapter 4. The behavior restrictions were covered in the section on classical lamination theory. Special cases of laminates were discussed to learn about laminate characteristics and behavior. Predicted and measured laminate stiffnesses were favorably compared to give credence to classical lamination theory. Then, the strength of laminates was discussed and found to be reasonably predictable. Finally, interlaminar stresses were analyzed because of their apparent strong influence on laminate strength (and life). 

We re almost ready to start naming molecules. We finished learning about the individual parts of a name, and now we need to know how to identify how the pieces are connected. For example, let s say you determine that the functional group is OH (therefore, the suffix is -ol), there is one double bond (-en-), the parent chain is six carbon atoms long (hex), there are four methyl groups attached to the parent chain (tetramethyl), and the double bond is cis. Now you know all of the pieces, but we must find a way to identify where all of the pieces are on the parent chain. Where are all of those methyl groups (and so on). This is where the numbering system comes in. First we will learn how to number the parent chain, and then we will learn the rules of how to apply those numbers in each part of the name. 

Stereoisomerism If there are any double bonds, we place the term cis or trans at the beginning of the name. If there is more than one double bond, then we need to indicate cis or trans for each double bond, and we must number accordingly (for example, 2-cis-4-trans. . . ). If there are any stereocenters, here is where we would indicate them for example, (2R,4S). Stereocenters are placed in parentheses. We will see more of this when we learn about stereocenters in the upcoming chapters. 

There are many reagents that will add across an alkene and completely cleave the C=C bond. In this section, we will learn about one such reaction, called ozonolysis. Consider the following example ... 

You might learn about the structure of DNA at the end of your organic chemistry course. For right now, we will be focused on problems that deal primarily with small molecules and therefore, for our purposes, we should think of H-bonding as an interaction a type of intermolecular force. 

The first half of our story builds up to reactions, and we learn about the characteristics of molecules that help us understand reactions. We begin by looking at atoms, the building blocks of molecules, and what happens when they combine to form bonds. We focus on special bonds between certain atoms, and we see how the nature of bonds can affect the shape and stability of molecules. At this point, we need a vocabulary to start talking about molecules, so we learn how to draw and name molecules. We see how molecules move around in space, and we explore the relationships between similar types of molecules. At this point, we know the important characteristics of molecules, and we are ready to use our knowledge to explore reactions. 

Prior to 1985, much had been learned about the chemistry of the silicon-carbon double bond through the study of the reactions of silenes with a wide variety of reactants. Thus it was known that all silenes studied reacted readily with alcohols (particularly methanol) by regiospecific addition across the ends of the Si=C bond in which the MeO group became attached to silicon and the alcoholic H to carbon, as in Eq. (22). 

In the less than three decades since silenes were first described by Gusel nikov and Flowers, an impressive amount of knowledge concerning silenes and the behavior of the silicon-carbon double bond has been discovered and reported. Several hundred papers have been published dealing with silenes in one context or another, and it is clear that the status of silenes has changed from that of rare oddity to a not uncommon occurrence. Much has been learned about their reactions, although much remains to be learned about the finer details of the mechanisms of some of their reactions. 

What developments are likely in the future Now that many reactions are known, the investigation of reaction mechanisms of disilenes is just beginning. Much is likely to be learned about details of reaction pathways. Further studies, both experimental and theoretical, should lead to a more complete understanding of the chemical bonding in disilenes. Vibrational spectra and electronic excited states of disilenes have received very little... 

As we learn about the distribution of electrons within a covalent bond, we start with a popular representation known as a Lewis structure. Figure 2.11 depicts the... 

In this chapter, you have learned about intermolecular forces, the forces between atoms, molecules, and/or ions. The types of intermolecular forces include ion-dipole forces, hydrogen bonding, ion-induced and dipole-induced forces, and London (dispersion) forces. 

In this section, you reviewed how to name and draw alkanes, alkenes, and alkynes. You also learned how to name aromatic hydrocarbons. The names of all the other organic compounds you will encounter in this unit are based on the names of hydrocarbons. In the next section, you will learn about organic compounds that have single bonds to halogen atoms, oxygen atoms, and nitrogen atoms. 

In this section, you learned how to recognize, name, and draw members of the alcohol, alkyl halide, ether, and amine families. You also learned how to recognize some of the physical properties of these compounds. In the next section, you will learn about families of organic compounds with functional groups that contain the C=0 bond. 

Trends for electron affinity are more irregular than those for atomic radius and ionization energy, because factors other than atomic size and Zeff are involved. In future chemistry courses, you will learn about these factors and how they explain the irregularities. However, the property of electron affinity is still significant when you consider it in combination with ionization energy. The trends that result from this combination are important for chemical bonding. 

In the next Unit, you will continue to examine chemical bonds, but with a different emphasis. You will learn about the energy changes that are associated with breaking and forming bonds. In other words, you will examine the energy changes of chemical reactions. 

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