A polar covalent bond is a type of bond between two or more atoms in which the atoms do not share their pair of electrons equally. In this type of bond, one of the atoms is stronger than the other and attracts the electrons so that they spend more time closer to the stronger atom.
As electrons are always negatively charged, this gives the stronger atom a slight negative charge due to its larger share of atoms. Similarly, the weaker atom becomes slightly positively charged so that the atoms balance each other out.
The most common example of a polar covalent bond is H2O, or water, which is made up of two hydrogen molecules and one oxygen molecule. In this bond, the oxygen atom has a stronger pull, so it gets the larger share of the electrons, giving it a partial negative charge.
In a polar covalent bond, one atom is stronger than the other due to the electronegativity difference between the two and the geometrical structure of the atoms. Hydrogen and chlorine are another example of molecules that form a polar covalent bond, with chlorine being the stronger atom in this situation. Other examples of polar covalent bonds include amines and peptide bonds.