Atoms that typically form covalent bonds with each other have similar electronegativity, which expresses the atom's tendency to attract electrons, such as with carbon and hydrogen, which form methane. They stand in contrast to ionic bonds, where electronegativities are vastly different, as with sodium and chlorine, which combine to form table salt. These actually exist on a continuum with significant but lesser differences in electronegativity causing the formation of polar molecules.Know More
Most bonds between atoms are at least somewhat covalent. Purely covalent bonds exist in molecules that contain only two or more atoms of the same element. Examples include oxygen, nitrogen, hydrogen and chlorine gases.
Molecules only really exist where the bonds between atoms have covalent character, which means that the electrons are at least partially shared by the member elements of the molecule. In fully ionic bonds, as in table salt, the bond between the ions is purely based on opposite charge, and each sodium ion in a pure salt crystal can be said to share an equivalent bond with each chloride ion surrounding it in its crystal lattice. If such an ionic compound were viewed as a molecule, it would actually be the size of the entire salt crystal.Learn more in Atoms & Molecules
Because they are the result of the attraction between partial charges rather than full charges, hydrogen bonds are much weaker than ionic or covalent bonds. Ionic and covalent bonds attract the atoms of different substances together to form the molecules of compounds, while hydrogen bonds are forces that tend to attract molecules to each other. An example of hydrogen bonding is the attraction between individual water molecules while the attraction between the atoms of hydrogen and oxygen within each water molecule represents covalent bonding.Full Answer >
Metals are the only substances that use metallic bonds among their atoms. While many elements are commonly known as metals, including iron, aluminum, gold, silver and nickel, metals include a variety of other elements as well. Most elements are metals, including some such as sodium, radium and calcium, which may not seem very metallic.Full Answer >
Coordinate covalent bonds, also known as coordinate links or semipolar bonds, are different from normal covalent bonds because both of the electrons that are shared by the bonded atoms originally come from the same atom. This contrasts with normal covalent bonds, in which each atom gives up one of the two electrons that form the shared electron pair.Full Answer >
Electrons are shared in a covalent bond when each of the participating atoms has roughly the same ability to attract electrons. The more evenly the two atoms are able to pull the participating electrons towards themselves, the more evenly the electrons share their time around each atom.Full Answer >