Polar covalent bonds and

Carbon-oxygen and carbon-halogen bonds are polar covalent bonds and carbon bears a partial positive charge in alcohols ( " C—0 ) and in alkyl halides ( " C—X ) Alcohols and alkyl halides are polar molecules The dipole moments of methanol and chloromethane are very similar to each other and to water... 

Dipole moment (n ), 38 halomethanes, 335 polar covalent bonds and, 38-39 table of, 39... 

Hydrogen bond A weak bond between the hydrogen in a polar covalent bond and a neighboring molecule with a highly electronegative atom. 

We know that the three types of chemical bonds that exist between atoms are non polar covalent bonds, polar covalent bonds and ionic bonds. We are already familiar with the idea that it is helpful to think of these as making up a bonding continuum. Non polar covalent bonding lies at one end of the continuum and ionic bonding at the other polar covalent bonding lies between these two extremes. 

We met the concepts of a polar covalent bond and electric dipole moment in Section 2.14. 

The difference between the electronegativity values of the atoms forming a bond within a molecule is used to determine whether the bond is covalent, polar covalent, or ionic. Generally, an electronegativity difference from 0 to 0.4 indicates a covalent bond a difference from 0.5 to 1.8 indicates a polar covalent bond and a difference of 1.9 or greater indicates an ionic bond. For example, the electronegativity differences for the bonds Cl-Cl, H-O, and Na-Cl are 0, 1.4, and 2.1, respectively, indicating that the bond types are covalent, polar covalent, and ionic, respectively. 

The organometallic compounds most likely to undergo hydrolysis are those with ionic bonds, those with relatively polar covalent bonds, and those with vacant atomic orbitals (see Chapter 1) on the metal atom, which can accept more electrons. These provide sites of attack for the water molecules. For example, liquid trimethylaluminum reacts almost explosively with water or water and air ... 

The difference between the electronegativity values of the two atoms involved in creating a chemical bond explains the ideas of bond character, bond polarity, covalent bonds, and ionic bonds. Figure 9.2 illustrates these concepts. 

Distinguish between a non-polar covalent bond and a polar covalent bond. 

Solution KCl has a metal and a nonmetal ion attracted to one another and it will be ionic. H301+ has polar covalent bonds and one coordinate covalent bond. The bond between C and Cl will be polar covalent because of the difference in electronegativities. Si02 is sand and is a network solid. A sample of iron will have metallic bonds because only metal atoms are present. Fluorine is diatomic and will have nonpolar covalent bonds. HBr will have a polar covalent bond because of the great difference in electronegativity between these two nonmetals. 

When we talk about the polarity of molecules, we are talking about whether the molecule has positive and negative poles, like a bar magnet. A polar molecule—that is, one with a positive and negative side—must contain one or more polar covalent bonds and it must have asymmetrical molecular geometry. A non-polar molecule either has symmetrical molecular geometry, or it only has non-polar covalent bonds, or both. This will be made clear as we go over some examples, but in the meantime, try to commit the little flowchart on page 139 to memory. 

Summarize As you read the chapter, identify the main ideas of bonding under the appropriate tabs. After you have read the chapter, explain the difference between polar covalent bonds and covalent bonds on the inside portion of your Foldable. 

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