The characteristic shape of water molecules—the bent shape—is caused primarily by the arrangement of electrons around the oxygen atom, including bonded and lone pairs, which create a polar molecule with a distinct geometry. This bent molecular structure leads to polarity because the polar O-H bonds do not cancel each other out. The arrangement forces the molecule into an angle of about 104.5 degrees rather than a straight line, making it polar with a partial negative charge near oxygen and partial positive charges near the hydrogens. This polarity causes strong hydrogen bonding between water molecules. Additionally, the characteristic shape of a water droplet (like a sphere or flattened sphere on surfaces) arises from intermolecular forces: cohesive forces (hydrogen bonding within water) create surface tension, which pulls the molecules into a shape with minimal surface area, typically a sphere. When water interacts with surfaces, adhesive forces balance cohesion, altering the droplet shape. Thus, water's molecular bent shape and strong hydrogen bonding are fundamental in producing its unique characteristics such as polarity, surface tension, and the shape of water droplets.
