[quantum_toothpaste]

Water molecules make a V shape rather than a straight line, why is that?

The angle is supposed to be 104.45 degrees.. how is that calculated?

[Jorriss]

http://en.wikipedia.org/wiki/VSEPR_theory read on this.

Summary version: electron pairs influence the geometry.

[uvcyclotron]

http://en.wikipedia.org/wiki/VSEPR_theory read on this.

Summary version: electron pairs influence the geometry.

Joriss is correct, you might be knowing that in a water molecule, the central O atom is in sp³ hybridization, where there are 2 bond-pair electrons, and 2 lone pair e^-, these arrange in a tetrahedral geometry in 3-D space, which results in the H--O--H bond appearing like a V.