Water and H-Bonding

1. WATER MOLECULES AND HYDROGEN BONDING
   1. Water is a polar molecule. Its polar bonds and asymmetrical shape give water molecules opposite charges on opposite sides.
      
      1. Four valence orbitals of O point to corners of a tetrahedron.
      2. 2 corners are orbitals with unshared pairs of electrons and weak negative charge.
      3. 2 corners are occupied by H atoms which are in polar covalent bonds with O. Oxygen is so electronegative, that shared electrons spend more time around the O causing a weak positive charge near H's.
   2. The polar molecules of water are held together by hydrogen bonds.
      1. Positively charged H of one molecule is attracted to the negatively charged O of another water molecule.
      2. Each water molecule can form a maximum of four hydrogen bonds with neighboring water molecules.
      3. Hydrogen bonding orders water into a higher level of structural organization.

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