Here's why:
* Electronegativity: Electronegativity is the ability of an atom to attract electrons in a bond. Oxygen has a much higher electronegativity (3.44) than hydrogen (2.20). This means oxygen has a stronger pull on the shared electrons in a bond with hydrogen.
* Polarity: The greater the difference in electronegativity between two atoms, the more polar the bond. The large electronegativity difference between oxygen and hydrogen results in a highly polar bond.
Example: In a water molecule (H₂O), the oxygen atom pulls the shared electrons towards itself, creating a partial negative charge (δ-) on the oxygen and partial positive charges (δ+) on the hydrogen atoms. This is what makes water a highly polar molecule.
Other elements, like nitrogen (N) and fluorine (F), also form polar bonds with hydrogen, but the difference in electronegativity is smaller than with oxygen.
