Chemical bonding

1. The electrostatic forces between charged particles    
first of all.... you have to know this two terms.

bond energy - the energy involved in the processes of bond forming and bond breaking, a measure of bond strength
electrostatic force - a force existing as a result of the attraction or repulsion between two charged particles.

• opposite charges attract each other  (eg. proton and proton)

• same charges repel each other (eg. proton and electron)

when attractive force is greater than repulsive force, a chemical bond is formed.  This is a situation in which a pair of electrons is simultaneously attracted to two atomic nuclei.  two oppositely charged particles approach each other, the potential energy decrease.   For many atoms, the formation of a chemical bond with another atoms leads to a decrease in the energy of the system.

When an atom is involved in a chemical bond, some of the atoms' orbitals are modified to allow electrons to be shared between two adjacent atoms. However,  atoms share electrons but not necessarily equally....this leads to the next topic

2. types of chemical bonding
In science 10, we learned that chemical bond can be either ionic or covalent and now in chem 11, covalent bonding can be divided into two new categories:  polar or non polar. This classification is based on whether the electrons are shared equally.
Here are the three types of bonding:

1. ionic bond - the electrons are transferred from metal to non metal.  
2. non polar bond- the electrons are shared equally
3. polar bond - the electrons are not shared equally

To find out which type of bond is formed, you have to know their electronegativity.
Electronegativity of an atom is the tendency of the atom to attract electrons from a neighbouring atom.
In general, values increase from left to right and decrease down a group
Most is flourine and least is celsium

when the difference of two atoms is:
less than 5... a covalent bond is formed
between 0.5 and 1.8....a polar covalent bond is formed
greater than 1.8... an ionic bond is formed

3.a closer look to polar covalent compounds
Polar covalent bonding
the atom with the great electronegativity will pull the electrons in the onds, move time will spend on this electron
the atoms:
with higher electronegativity will form a partial negative charge
with lower electronegativity will form a partial positive charge

here is a more detailed video about polar covalent compounds