Answer
Bond Polarity is the formation of polar ends on two bonded atoms due to the unequal distribution of electrons between them. Electronegativity difference between the bonded atoms leads this phenomenon.
Work Step by Step
This is how Electronegativity difference affects the bonding:
If the Electronegativity Difference is in between 0.0 to 0.2 a Non-polar covalent bond is formed.
If the Electronegativity Difference is in between 0.3 to 1.4 a Polar covalent bond is formed.
If the Electronegativity Difference is greater than 1.5 an Ionic bond is formed.