What are covalent bonds?

The chemical bonds which are formed by sharing between two or more non-metals only are called covalent bonds.
Covalent bonds can be divided into three types based on how many pairs of electrons are being shared between the atoms –
SINGLE COVALENT BOND – The covalent bonds in which only 1 pair of are shared between atleast two atoms are known as single covalent bonds.
For example,
So, in the image above you can see a single pair of electrons being shared between two hydrogen atoms.
Double covalent bonds – The covalent bonds in which two pairs of valence electrons are shared between atleast two atoms are known as double covalent bond.
For example,
In this image don’t get confused by the two shells. Only focus on the valence shell ie. the last shell and you will be able to find out that three pairs of valence electrons are being shared.
Triple covalent bonds – The covalent bonds in which three pairs of valence electrons are shared between atleast two atoms are known as triple covalent bond.
For example,
In this image too, focus only on the last shell and you will be able to see three pairs of electrons being shared between two nitrogen atoms.