Water (H2O) should be drawn as two hydrogen atoms connected to one oxygen atom by a bond known as a polar covalent bond. There are two lone pairs of electrons on each oxygen atom (represented by the two short lines). The oxygen has a slightly negative charge while the hydrogen has a slightly positive charge. When two water molecules are in the vicinity of one another, the slightly negative oxygen atom of one molecule is attracted to the slightly positive hydrogen atom of the other water molecule and this forms a hydrogen bond. This results in cohesive forces between water molecules.