Types of Chemical Bonding
By Meredith Marcum
First, let's talk about what chemical bonding is. A chemical bond is a mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together. The reason atoms bond to each other is to lower their potential energy and become more stable. The way that atoms distribute their electrons determines how they bond. There are 3 types of chemical bonding: ionic, covalent and metallic. I am going to explain in-depth about each of these types and how to classify them.
Ionic Bonds are chemical bonds that result from the electrical attraction between cations and anions. Ionic bonds are between nonmetals and metals. There are rarely just purely ionic bonds in nature, they usually differ based upon how strongly the atoms of each element attract electrons. An example of an ionic bond is NaCl, because sodium is giving it's electrons to Chlorine.
Covalent bonds result from the sharing of electron pairs between two atoms. They occur between a nonmetal and a nonmetal. Just like ionic bonds, there are rarely purely covalent bonds in nature and they can be determined the same way as ionic bonds. There are two different types of covalent bonds, polar and non-polar.
Non-polar covalent bonds are when the electrons are shared equally by the bonding atoms, resulting in a balanced distribution of electrical charge. An example is the bond between two hydrogen atoms.
Polar covalent bonds are when the bonded atoms have an unequal attraction for the shared electrons. An example is HCl, The result is a bond where the electron pair is displaced toward the more electronegative atom. This atom then obtains a partial-negative charge while the less electronegative atom has a partial-positive charge.
Metallic bonds result from the attraction between metal atoms and the sea of electrons surrounding it. Metallic bonds are between metals and metals. Within a metal, the vacant orbitals outer energy levels overlap. This overlapping of orbitals allows the outer electrons to roam freely throughout the entire metal. The electrons are delocalized which means they do not belong to any specific atoms but move freely about the metal's network of empty atomic orbitals. Examples for materials having metallic bonds are most metals such as Cu, Al, Au, Ag etc.
Determining Bond Type
The first way to determine the bond type is to calculate the electronegativity difference. The difference can be tested on a scale that ranges from 0%-100% and 0-3.3.
The other way is to observe the characteristics that the element possesses, just like we did in the bond types lab.