Chemical Properties of Water

Chemical Structure
Water is a special chemical substance consisting of two atoms of hydrogen and one atom of
oxygen.

O--H bond length = 95.7 picometers
H--O---H angle = 104.5°
O-H bond energy = 450 kJ/mol
Dipole moment = 1.83 debyes

The hydrogen atoms are "attached" to one side of the oxygen atom, resulting in a water molecule
having a positive charge on the side where the hydrogen atoms are and a negative charge on the
other side, where the oxygen atom is.
Since opposite electrical charges attract, water molecules tend to attract each other,
making water kind of "sticky."
The side with the hydrogen atoms (positive charge) attracts the oxygen side (negative charge)
of a different water molecule.

The water molecule maintains a bent shape because of two considerations:
1. The tetrahedral arrangement around the oxygen.
2. The presence of lone pair electrons on the oxygen.
Two electrons not involved in the covalent bonds are called lone pair electrons.
The pairs of electrons are left alone.
These lone pairs are very negative - containing two negative electrons each - and want to
stay away from each other as much as possible.
These repulsive forces act to push the hydrogens closer together. The net result is a
terahedral arrangement.
Tetrahedral means "four-sided". It is the arrangement of four atoms around a central atom
such that the distance between them is maximized.
The arrangement adopted will be the form of a regular tetrahedron.
It has regular bond angles of 109.5°.
If we do a similar arrangement of water, putting oxygen in the center, and using the
two hydrogens and two lone pairs at the corners, we also come up with a tetrahedral
arrangement.
Because we don't "see" the electrons, the resulting tetrahedron "looks" BENT