Electron sharing, covalent bonds

Pure (nonpolar) Polar covalent bond covalent bond electrons shared... 

In a coordinate covalent bond, electrons shared between two atoms are contributed by just one of the atoms. As a result, the bonded atoms exhibit formal charges. 

The atoms in the molecules of these pain relievers are covalently bonded. Electrons are shared between atoms in a series of single and double covalent bonds. The covalent bonds in aspirin, acetaminophen, and ibuprofen are similar to those found in methane and carbon dioxide. 

Atoms do not all have the same ability to attract electrons. When two different types of atoms form a covalent bond by sharing a pair of electrons, the shared pair of electrons will spend more time in the vicinity of the atom that has the greater ability to attract them. In other words, the electron pair is shared, but it is not shared equally. The ability of an atom in a molecule to attract electrons to it is expressed as the electronegativity of the atom. Earlier, for a homonuclear diatomic molecule we wrote the combination of two atomic wave functions as... 

When the electrons in a covalent bond are shared equally, the length of the bond between the atoms can be approximated as the sum of the covalent radii. However, when the bond is polar, the bond is not only stronger than if it were purely covalent, it is also shorter. As shown earlier, the amount by which a polar bond between two atoms is stronger than if it were purely covalent is related to the difference in electronegativity between the two atoms. It follows that the amount by which the bond is shorter than the sum of the covalent radii should also be related to the difference in electronegativity. An equation that expresses the bond length in terms of atomic radii and the difference in electronegativity is the Schomaker-Stevenson equation. That equation can be written as... 

Covalent bonding is the sharing of one or more pairs of electrons by two atoms. The covalent bonds in a molecule a covalently bonded compound are represented by a dash. Each dash is a shared pair of electrons. These covalent bonds may be single bonds, one pair of shared electrons as in H-H double bonds, two shared pairs of electrons as in H2C=CH2 or triple bonds, three shared pairs of electrons, N=N . It is the same driving force to form a covalent bond as an ionic bond—completion of the atom s octet. In the case of the covalent bond, the sharing of electrons leads to both atom utilizing the electrons towards their octet. 

If two like atoms form a covalent bond by sharing an electron pair, for example... 

The key to understanding the properties of water lies in the nature of something called the hydrogen bond. I introduced covalent bonds, the sharing of a pair of electrons between two atoms, back in chapter 3. Hydrogen bonds are another matter. 

Elements in organic compounds are joined by covalent bonds, a sharing of electrons, and each element contributes one electron to the bond. The number of electrons necessary to complete the octet determines the number of electrons that must be contributed and shared by a different element in a bond. This analysis finally determines the number of bonds that each element may enter into with other elements. In a single bond two atoms share one parr of electrons and form a a bond. In a double bond they share two pairs of electrons and form a a bond and a tt bond. In a triple bond two atoms share three parrs of electrons and form a cr bond and two tt bonds. 

Similarly, hydrogen and fluorine can form a covalent bond by sharing electrons. By doing this, hydrogen fills its only shell and fluorine achieves its valence shell of eight electrons. 

Atoms other than hydrogen also form covalent bonds by sharing electron pairs, and the electron-dot structures of the resultant molecules are drawn by assigning the correct number of valence electrons to each atom. Group 3A atoms (such as boron) have three valence electrons, group 4A atoms (such as carbon) have four valence electrons, and so on across the periodic table. The group 7 A element fluorine has seven valence electrons, and an electron-dot structure for the F2 molecule shows how a covalent bond can form ... 

Note the differences between crystal field theory and valence bond theory. In crystal field theory, there are no covalent bonds, no shared electrons, and no hybrid orbitals—just electrostatic interactions within an array of ions. In complexes that contain neutral dipolar ligands, such as H20 or NH3, the electrostatic interactions are of the ion-dipole type (Section 10.2). For example, in [Ti(H20)g]3+, the Ti3+ ion attracts the negative end of the water dipoles. 

Carbon can form multiple covalent bonds by sharing more than two electrons with a neighboring atom (Section 7.5). In ethylene, the two carbon atoms share four electrons in a double bond. In acetylene, the two carbons share six electrons in a triple bond ... 

In a coordinate covalent bond, the shared electrons are furnished by only one species. Which of the following molecules is LEAST likely to be involved in a coordinate covalent bond ... 

A is correct. Sodium chloride is a protolypic example of an ionic bond. In a coordinate covalent bond, both shared electrons come from the same atom for instance, a Lewis base (i.e., ammonia) or oxygen-containing compound (i.e., water). Although both shared electrons come from the same atom, a coordinate covalent bond is a single bond similar in chemical properties to a covalent bond. 

Covalent bonds involve sharing of valence electrons to complete electron shells. For each bond, two electrons are shared. Covalent bonds are generally tighter than ionic bonds. In many compounds the bonding is intermediate between ionic and covalent. 

In atomic crystalline solids, atoms are covalently bonded to each other. In covalent bonding, electrons are shared equally by the bonding atoms. 

Carbon, with four valence electrons, mainly forms covalent bonds. It usually forms four such bonds, and these may be with itself or with other atoms such as hydrogen, oxygen, nitrogen, chlorine, and sulfur. In pure covalent bonds, electrons are shared equally, but in polar covalent bonds, the electrons are displaced toward the more electronegative element. Multiple bonds consist of two or three electron pairs shared between atoms. 

Gilbert Newton Lewis described covalent bonds as sharing electrons in the 1910s and the electron pair donor/acceptor theory of acids and bases in the... 

In a polar covalent bond, the shared electrons are shared unequally, being pulled more toward the atom with the higher electronegativity. As shown in Table 9.1, an electronegativity difference of 0.3 to 1.4 characterizes a polar covalent bond. This unequal electron... 

Carbon can form multiple bonds (double or triple bonds see Ch. 1) between its atoms when forming compounds. This can be shown in some simple hydrocarbons (see Fig. 2.2). In covalent bonds, the sharing of a pair of electrons comprising one electron from each atom involved in the bond is called a single bond and is represented by a single line. The bond is formed by two electrons for example, in ethane, C2H6 ... 

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