Oxygen has a much higher electronegativity than hydrogen, meaning it pulls shared electrons toward itself. Because of this unequal sharing, water molecules are highly polar with distinct partial electrical charges. The oxygen atom carries a partial negative charge, while the hydrogen atoms carry partial positive charges.
This built-in polarity allows neighboring water molecules to form strong electrostatic connections called hydrogen bonds. This extensive hydrogen bonding network gives liquid water several highly unusual physical and chemical properties. It has an exceptionally high boiling point compared to similar molecules of the same size.
Water also has a very high specific heat capacity, meaning it absorbs vast amounts of thermal energy. A common student misconception is that water conducts electricity perfectly on its own. Pure water is actually an excellent insulator and does not conduct electrical current well at all.
It only conducts electricity when dissolved ionic salts are freely floating within the liquid mixture. As a highly effective solvent, water effortlessly dissolves many ionic compounds and polar organic molecules. This dissolving power facilitates critical biochemical reactions and nutrient transport processes inside living biological cells.