Carbon: many people know what it is, but only a few know what it does. Organic chemists are most familiar with the element and the magnitude of its usefulness. However, one does not have to have a Ph.D in Organic Chemistry to gain a better understanding and appreciation of this fundamental element.
So why carbon? As one of the earth's most abundant elements, carbon is capable of bonding with several other elements. At the atomic level, the most common version contains six protons, six neutrons, and six electrons. In other words, that set up singly identifies carbon among the other elements without the inclusion of isotopes (C13 and C14). The stability of a carbon molecule depends largely upon its distribution of electrons. In order to achieve full stability, its valence, or outer electrons must equal eight. A single carbon atom has four valence electrons and is in a desperate search for four more to complete its octet. As such, it has the potential to form covalent bonds of equal or unequal electron distribution with many elements. If present, carbon easily bonds with tiny hydrogen atoms to form the scentless methane, or CH4.
Furthermore, carbon is notorious for forming covalent bonds with itself. It does so very readily, as evidenced by incredibly long polymer chains. These polymer chains are the foundation of plastics like the Oreo cookies container, or the case of a CD. Furthermore, plastics are essential to industry, so a lot of research and production methods are currently being explored to further develop the use of carbon. Moreover, polymerized carbon may be in alkene or alkyne form, alluding the presence of a strong double and triple bond, respectively.
The double or triple bond forms are interesting insofar as they may have resonance activity. For example, benzene, a common aromatic carcinogen found in gasoline, is a hexagonal arrangement of carbon atoms consisting of alternate double and single bonds. Research has shown the electron density to be even throughout molecule, thus indicating resonance movement. Resonance is also common with multi-element compounds that include carbon such as aldehydes, alcohols, ketones, sulfides, carboxylic acids, amines, etc.
Generally, the aforementioned compounds denote carbon's relationship with oxygen, sulfur, and nitrogen. The difference in electron negativities among the atoms give the molecule a polarity that may influence its reactivity and solubility. More important, these molecules are integral in sustaining biological life. Every organism, including humans, have a high percentage of carbon. The carbohydrates consumed and digested are complex arrangements of carbon and oxygen, and the amino acids essential to enzyme function contain carbon, oxygen, and nitrogen. Moreover, carbon is the air humans exhale. Plants provide humans with oxygen due their ability to process carbon dioxide. Basically, without carbon, the human race would be reduced to nothing.
Overall, carbon's four electron vacancies allow it to bond with itself and other elements readily and conveniently. And most often these molecules are very stable. As a result, it is evidenced in a variety of molecules useful to humans. Carbon is the ground on which they walk, the plastic of their toys and food storage, the rubber of their tires, the substances of their bodies, and ultimately the life of which they live.