water

n Physical properties-the result of hydrogen bonding
Studied in isolation, the water molecule is deceptively simple. Its tow hydrogen atoms are joined to the oxygen atom by single covalent bonds. Because oxygen is more electronegative than hydrogen, the electrons of the polar bonds spend more time closer to the oxygen atom. In other words, the bonds that hold together the atoms in a water molecule are polar covalent bonds, with the oxygen region of the molecule having a partial negative charge and the hydrogen having a partial positive charge. The water molecule, shaped something like a wide V, is a polar molecule, meaning that opposite ends of the molecule have opposite charges.
The anomalous properties of water arise from attractions between these polar molecules. The attraction is electrical; slightly positive hydrogen of one molecule is attracted to the slightly negative oxygen of a nearby molecule. The two molecules are thus held together by a hydrogen bond (FIGURE 1). Each ...