What type of bond exists between atoms in a molecule of water?

In a molecule of water (H₂O), a polar covalent bond is present between the hydrogen and oxygen atoms. This type of bond occurs when two atoms share electrons unequally due to a difference in electronegativity. Oxygen is more electronegative than hydrogen, meaning that it has a greater tendency to attract electrons. As a result, the shared electrons spend more time closer to the oxygen atom, leading to a partial negative charge on the oxygen and a partial positive charge on the hydrogen atoms.

This polarity of the water molecule is crucial because it contributes to many of water’s unique properties, such as its ability to dissolve various substances and its high specific heat capacity. These properties are important for biological systems and contribute to water's role as the "universal solvent."

While hydrogen bonds are indeed significant in the interactions between water molecules, they do not represent the bond that directly holds the hydrogen and oxygen atoms together within a single water molecule. In contrast, nonpolar covalent bonds occur when atoms share electrons equally, and ionic bonds involve the transfer of electrons from one atom to another, neither of which apply to water’s structure.