By the sharing of electrons between two atoms that can complete their valence shell mutually is a covalent bond. In the formation of a hydrogen molecule, the two hydrogen atoms with one electron each, forms a covalent bond by the sharing of electrons. To the electron pair that is shared, each atom shares one of the electrons among the electron pair contributing the valence of both the atoms. The chemical bonding which is referred to by the sharing of electrons is known as the covalent bonding.
Pure bonds of Covalent;
A form of chemical bonding which characterized by the sharing of pair of electrons between the atoms are called as covalent bonds. The attraction or the repulsion stability that exerts between the atoms when they share electrons is called as covalent bonding. Covalent bonds includes the several kinds of interactions such as sigma (‘sigma’) bond and the pie (‘Pi’ ) bond. Out of these two bonds the sigma bond are much stronger than the pie bonds. The prefix used ‘co’, which means the joining thus covalent means the joining of the valence electrons. The theory based on the covalent bond is called the valence bond theory. The property of joining atoms by the covalent bonds is greatest in the atoms having the similar electro negativities. So that the covalent bonding does not require the two atoms of the same element necessarily but they need only the atoms of the comparable electro negativity. The strength of the covalent bonds depends on the angular relations between the atoms of the polyatomic molecules. There are several types of the covalent bonds as the double bond and the triple bond.
Covalent Bond Structure:
Characterized by the sharing of electrons between different atoms, a form of chemical bonding is a covalent bond. The formation of attraction to repulsion stability during the sharing of electrons between atoms is called covalent bonding. Using a Lewis dot structure helps in the representation of the molecules in a much simpler way. For example, the covalent bond between the two hydrogen atoms in a hydrogen molecule can be represented as below:
H· + H·’->’ H:H
The electron pair that is shared between the two atoms contributed by both the atoms may also be represented as
H· + H·’->’ H-H
Hydrogen atom being the simplest molecule of all the compounds has only one covalent compound. When complex atoms result in the formation of covalent bonds, the molecules formed as a result are also complex that involves a number of covalent bonds. An atom may have valence electrons, called the lone pairs, which does not involve in the formation of covalent bond.
A single covalent bond involves the sharing- covalent Bond
G.N. Lewis was the first to suggest, in 1916, that atoms may combine with one another by sharing of electrons in their valency shells so that the combining atoms attain the nearest noble gas configurations. The shared electrons contribute towards the stability of both the atoms. This type of linkage is called covalent Linkage or Covalent Bond. The compounds formed by this mechanism are called covalent compounds. The number of electrons which an atom contributes for sharing in a covalent bond is called its covaleny. Thus, covalence of hydrogen, chlorine, oxygen, and nitrogen is 1, 1, 2, and 3, respectively. Thus there is decrease in energy in the formation of an ionic bond.
A single covalent bond involves the sharing of covalent bond: Atomic orbital Theory of Covalent bond
Atomic orbital Theory of Covalent bond: The atomic orbital theory can accommodate a maximum of two electrons having opposite spins. As long as such electron pairs are present in atomic orbitals, they are not available for chemical combination. Thus, according to atomic theory formation of a covalent bond between two atoms results from the coupling of electrons with opposite spins belonging to half-filled atomic orbitals of outer shells of the two atoms. This invariably leads to lowering of potential energy of the system.
A single covalent bond involves the sharing of covalent bond: Valence Bond Theory (VBT)
The valence bond theory can be described as the wave mechanical expression of the lewis concept of an electron-pair bond. In this theory, the atoms are considered to retain their individuality and the bond arises from the interactions of valence electrons as the atoms come closer together. The basic approach of VBT is thus closely related to our conventional ideas of localized chemical bonds.
Valence bond theory was first proposed by W. Heitler and F. London in 1927 and later extensively developed by Linus Pauling and J.C. Slater. L. Pauling was rewarded in the year 1954 chemistry Nobel Prize for elucidating the nature of the chemical bond and the structure of proteins.
Thus, we can illustrate the theory by considering the formation of a hydrogen molecule. Thus we can give the Intermolecular bonding as: The electron-pair bond forms through the interaction of an unpaired electron on each of two atoms.
There will be an opposite spinning of the electrons.
When the electrons get paired with the other they could not be able to involve in the additional bonding.
A single covalent bond involves the sharing of covalent bond: Linus Pauling applied various on VBT was found to be:
The exchange of electrons for bond involves only one wave function for each atom.
The electrons in the lowest energy level are obtained from the strongest bonds.
Of the two orbitals in an atom, the one orbital can overlap the other with an orbital from another atom will figure out the strongest bond, and this tie will be likely to lie in the direction of the intense orbital.
A single covalent bond involves the sharing of covalent bond : The molecular Orbital Theory (MOT):
The Mot was put forth by F.Hund and R.S. Mulliken and further by J.E. Lennard jones and Charles Coulson. R.S. Mulliken was awarded the 1966 Chemistry Nobel prize for his contributio0ns to MOT.
According to MOT, a molecule is considered to be quite different from the constituent atoms. All the electrons belonging to the atoms constituting a molecule are considered to be moving along the entire molecule under the influence of all the nuclei. Thus, a molecule is supposed to have orbitals of varying energy levels in the same way as an isolated atom has. These orbitals are called molecular orbitals.
Multiple Covalent Bonds
When the two atoms that are covalently bound are shared by only one pair of electrons, it is called a single bond. When the atoms are shared by two and three electron pairs, it is known as a double or a triple bond respectively. The first bond formed between the two atoms is called the sigma (σ) bond and all the other bonds are called the pi (π) bonds.
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