Final answer:
Water molecules interact due to their polar nature, with the oxygen atom having a partial negative charge and the hydrogen atoms a partial positive charge. This creates a dipolar molecule that forms strong hydrogen bonds, significantly affecting the physical properties of water and making it a crucial solvent.
Step-by-step explanation:
Pure water consists of water molecules that interact strongly with each other, which is mainly due to their polar nature. A water molecule, H₂O, is considered a polar molecule because it has an uneven distribution of electron density. This leads to part of the molecule having a slight positive charge, while the other part has a slight negative charge, denoted as δ+ (delta positive) and δ- (delta negative), respectively.
The oxygen atom in a water molecule is more electronegative than the hydrogen atoms, meaning it attracts electrons more closely. This causes the oxygen atom to have a higher electron density, resulting in a partial negative charge. Conversely, because the oxygen atom attracts the shared electrons more strongly, the hydrogen atoms end up with a partial positive charge. The representation of these charges within a molecule by δ+ and δ- symbols helps to understand why water molecules have a dipole moment and can form hydrogen bonds with each other, which are stronger than conventional dipole-dipole interactions.
These hydrogen bonds immensely influence the physical properties of water, making it a unique solvent which is vital in many biological and chemical processes. The highly polar nature of water molecules facilitates interactions with other polar substances, playing a crucial role in human physiology and the behavior of many compounds.