What is co valent bond

 
Covalent bond: The bond formed by mutual sharing of valency electrons in order to get stable electronic configuration of nearest inert gas is called covalent bond. Generally this bond is formed between non metals.
Based on type of atoms participated in the bonding, covalent bond is classified into two types. They are (i) polar covalent bonding
(ii) Non-polar covalent bonding
(i)                  Polar covalent bond: The bond formed between atoms of different electronegativity is called polar covalent bond. Ex: HCl, HF, HBr, H₂O, NH₃…etc
(ii)                Non –polar covalent bond: the bond formed between atoms of similar electronegativity is called non-polar covalent bond. Ex: H₂, O₂, N₂, Cl₂…etc.

In a covalent bond shared pair of electrons is known as Bond pair. Bond pair is represented by a line.
Based on number of electrons shared between the atoms the covalent bonds are classified into three types: Single covalent bond, Double covalent bond and Triple covalent Bond.
 
Examples of Covalent Bond:
 
Hydrogen molecule is formed by the sharing of one electron pair (single bond) between two hydrogen atoms.


Oxygen molecule is formed by the sharing two electron pairs (double bond) between two oxygen atoms.


Nitrogen molecule is formed by the sharing of three electron pairs (triple bond) between two nitrogen atoms.