Answer: Difference in electronegativity between elements
Explanation:
Electronegativity is the power of an atom to attract an electron to itself. It is used to predict whether a bond between atoms will be IONIC or COVALENT, AND can also be used to predict if the resulting molecule will be POLAR or NONPOLAR.
A Slight difference in the electronegativity of elements explains the best supporting evidence for polarity in covalent bonded molecules.
A good example is WATER MOLECULE (H2O). Oxygen has 3.44, while Hydrogen has 2.20
So, the electrons are unequally shared, with the oxygen atom having more electron density than the hydrogen atoms. Thus, it carries a partial negative charge.
