A covalent bond also known as the molecular bond is a type of bond seen between the atoms where sharing of electrons are seen. The pair of electrons that are participating in this type of bonding is known as shared pair or bonding pair.
The covalent bond is witnessed between two atoms of the same element or of elements close to each other in the periodic table. A covalent bond is witnessed in the metals as well as non-metals. Sharing of bonding pairs helps the atoms to attain stability in their outer shell which is similar to the atoms of noble gases.
A covalent bond is witnessed between atoms of the same element.
Example: Bonding in the hydrogen molecule, Bonding in chlorine molecule.
A covalent bond is witnessed between atoms of different elements such as:
Example: hydrogen chloride (HCl) where the hydrogen and chloride combine to form the resultant, carbon dioxide (CO2) formed by the combination of carbon and oxygen.
Covalent bonds are formed between non-metal atoms. Each of the atoms involved in bonding contributes one, two, three or more electrons to form the shared pair.
Covalent bonds are classified as follows:
- Single covalent bond
- Double covalent bond
- Triple covalent bond
There are 4 types of chemical bonds that are formed by atoms or molecules to yield the resultant compounds. The stability of the resultant compound is measured by knowing the chemical bond of the compound. The types of chemical bonds are:
- Ionic Bonds
- Covalent Bonds
- Hydrogen Bonds
- Polar Bonds
Ionic bonding is a type of chemical bonding which includes the transfer of electrons from one atom or molecule to another. Here, an atom loses an electron and is in turn gained by another atom. When such an electron transfer takes place, one of the atoms in the molecule develops a “-ve“ charge and is known as an anion.
Another atom which develops a “+ve“ charge and is called the cation. The ionic bond gains strength from the difference in charge between the 2 atoms. The higher the charge difference between the cation and the anion, the stronger is the ionic bond in the molecule.
A covalent bond indicates the sharing of electrons between atoms and is commonly seen in organic compounds. Compounds which comprise of carbon generally display this kind of covalent bonding. The pair of electrons shared by 2 atoms now extend around the nuclei of atoms, leading to the creation of a molecule.
The hydrogen bond is also known as H-bond. A hydrogen bond is a formed due to the significant electrostatic force of attraction witnessed between the covalently bound hydrogen atom and a stronger electronegative atom or group, especially the elements belonging to the second row of the periodic table which includes oxygen, nitrogen, or fluorine.
Hydrogen bond creates a tendency for the hydrogen to get drawn towards the negative charges of any neighboring atom. This type of chemical bonding is called a hydrogen bond.
2 atoms connected by a covalent bond exercise different attractional forces, producing an uneven charge distribution in the bond. The resultant bond is shown as a polar bond. A polar bond is formed as an intermediate case between ionic and covalent bonding with one end having the lightly negatively charged molecule and the other end having a slightly positively charged molecule.
Inequalities in charge distribution in water are as shown in the figure.
Water is an ideal example to display the polarity of the molecule. Here, the oxygen end is lightly positively charged and the hydrogen ends are negatively charged. Hence, the polarity seen in water explains why some substances immediately dissolve in H2O and other substances do not dissolve.
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