If all four bonds are single, as in methane, the shape of the molecule is that of a tetrahedron. These bonds are oriented in definite directions in space, giving rise to the complex geometry of organic molecules. Actually, the only purely covalent bond is that between two identical atoms.Ĭovalent bonds are of particular importance in organic chemistry because of the ability of the carbon atom to form four covalent bonds. As a result, the bond has a partly ionic character and is called a coordinate link. ![]() In certain cases, however, both electrons come from the same atom. In most covalent bonds, each atom contributes one electron to the shared pair. For example, in methane (CH 4), carbon shares an electron pair with each hydrogen atom the total number of electrons shared by carbon is eight, which corresponds to the number of electrons in the outer shell of neon each hydrogen shares two electrons, which corresponds to the electron configuration of helium. By sharing their electrons, both atoms are able to achieve a highly stable electron configuration corresponding to that of an inert gas. If the atoms share more than two electrons, double and triple bonds are formed, because each shared pair produces its own bond. There is no net charge on either atom the attractive force is produced by interaction of the electron pair with the nuclei of both atoms. The Covalent BondĪ single covalent bond is created when two atoms share a pair of electrons. Thus the entire crystal is a single giant molecule. In an ionic crystal like sodium chloride, no discrete diatomic molecules exist rather, the crystal is composed of independent Na + and Cl − ions, each of which is attracted to neighboring ions of the opposite charge. The highly stable ions that result retain their individual structures as they approach one another to form a stable molecule or crystal. The atoms of metallic elements, e.g., those of sodium, lose their outer electrons easily, while the atoms of nonmetals, e.g., those of chlorine, tend to gain electrons. ![]() The ionic bond results from the attraction of oppositely charged ions.
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