Bonds

POLAR BONDS

The bonds formed between two dissimilar atoms are called as polar bonds. Such molecules with polar bonds are called as POLAR MOLECULES.
As we all know that no two atoms can have  same electronegativities therefore whenever two different atoms are brought together in a molecule the electronegativity difference between these two atoms would make the bonded pair of electron to till a little toward more electronegative atom making that atom or part of molecule Partially negative. Similarly the other atom or part of molecule would become partially positive. Thus two different polls would emerge upon the molecule. One positive pole and the other one negative pole.

Consider the following water molecule. Water is made of a more electronegative oxygen atom and a much lesser electronegative Hydrogen atom. Thus the electron density has shifted towards oxygen atom making it Partial negative. Similarly the shift of electron density away from the hydrogen has made it partial positive as shown in the figure below.