What is the final relationship between the atoms in a covalent bond?

Electronegativity in atoms causally relates to polarity in molecules, as different electronegativities in different components of an asymmetrical molecule cause that molecule to be polar. However, electronegativity differences that are too great lead not to polar molecules, but to ionic bonds. Electronegativity differences also do not lead to polar molecules when they are fully symmetrical because the charges are balanced.