Explain why the water molecule is V-shaped with 104 degrees.

Water is composed of two hydrogen atoms covalently bonded
to a single oxygen atom.  Each hydrogen atom shares a pair of electrons with the oxygen
atom, resulting in a slight positive charge on the hydrogen atoms and a slight negative
charge on the oxygen atom, otherwise known as a "dipole moment" or polar charge.
 Normally, the molecule would have tetrahedral geometry with 109.5 degrees between
atoms, but the molecule actually has a non-linear geometry because the negative charges
try to minimize their overlap, and the angle is reduced slightly to 104.5
degrees.