Water is something we can’t live without; roughly 70% of an adult human body is composed of water. I will be writing a followup post about the properties, but for now lets just focus on the molecular structure.
I made the model below to show its shape. The red centre is oxygen, the two whites are hydrogen, and the two empty red prongs represent two lone pairs.
The presence of two lone pairs means lots of repulsion between them, which pushes the two sets of bonded pairs closer together, so the two atoms of hydrogen are forced closer together to form a V shape.
Based on this we can predict the shape for hydrogen sulfide (H2S), bent for the same reasons H2O is bent, see below:
and also the oxonium ion H3O+
This oxonium ion is pyramidal as it is isoelectronic with ammonia, see previous post.
I highly recommend visiting Wolfram Alpha, simply type in a formula, name or equation and a treasure of information comes up.