Introduction
Chemical bonds play an important role at molecular level in chemistry. They link together different atoms in order to formulate a molecule. This results in formation of unique elements and compounds. In chemistry, there are 3 types of links—ionic, metallic and covalent. All of them work upon different principles. This article focuses on bonds covalent.
History
Remember, in your school your teachers used to teach you the importance of sharing. As per them, sharing of items between 2 friends increases their mutual love and concern towards each other. Covalent bonds seem to follow this idea because their formation is based on mutual sharing. Sharing of electrons during formation of bonds covalent grants a stable (inert gas like) electronic configuration to the sharers.
Generally, bonds covalent are bifurcated into 3 broad categories: single, double and triple. Number of bonds present between the atoms determines the strength and state of its molecules.
Single links are formed when 2 or more atoms mutually share a single pair of electrons. Similarly, sharing of two and three electron pair leads to the formation of double and triple bonds covalent. Due to unique sharing of electrons, no net charge is associated with all the sharers. Likewise, attractive forces are produced which keep the sharers in place. These forces are products of interaction between positively charged nuclei and negatively charged electrons of the atoms.
Features
Example:
The best example of these links is Methane (CH4)—an important hydrocarbon extensively studied in organic chemistry. The chemical structure of methane illustrates that 4 electrons are shared between 1 carbon and 4 hydrogen atom thereby forming long, open chains. Thus, the electronic configuration of methane is 8, which is similar to that of Neon (an inert gas).
Usually, 2 different atoms come in close vicinity and contribute individual electrons to form bonds covalent.
Nevertheless, special type of covalent bonds, known as co-ordinate bond may sometimes exist in certain compounds. Co-ordinate bonds are covalent in nature however in this case, only one atom contributes to sharing thereby creating 1 donor and 1 receiver atom. This grants a somewhat ionic character to the compounds.
Importance:
Bonds covalent are of great importance in organic and biochemistry. It is because of these links up that scientists are able to determine the orientation, geometry, structure and rotation of a compound.
The significance of these links was first discovered and established in 1916 by G.N. Lewis, an American chemist. He stated a peculiar observation that those molecules that carry atoms having odd number of electrons show a much stable molecular structure as compared to those that have even number of electrons. He formed an octet rule which helps scientists in determining the bond length, structure and distribution of charge on ions and molecules of a compound.
This rule was further supported by Pauli’s Exclusion principle and MOT (Molecular Orbital Theory).
Tips and comments
Factors Affecting Them:
Chemical bonds, especially bonds covalent are influenced by the electro-negativity of the linked atoms. When two participating atoms are equally negative, they well form non-polar bonds (like Hydrogen bonds in water H-H). Likewise, unequal distribution of electro-negativity causes formation of polar bonds (for instance, the links existing in HCl: H-Cl).
Overall, the chemistry of bonds covalent is comprehensive but interesting. If you wish to acquire more information on this topic, you can refer to scientific journals and online databases.
