# How does vsepr theory classify molecules?

##### 1 Answer

Valence shell electron pair repulsion theory (vesper for short) classifies molecules on the basis of the number of electron pairs, bonding and lone pairs, associated with the central atom.

#### Explanation:

It is a fact that electron pairs arranged around a central atom repel each other (hence vesper). In the molecule, they assume a shape, a geometry, that will minimize electronic interaction. These shapes can correspond to the Platonic solids: 2 pairs, linear; three pairs, trigonal planar; 4 pairs, tetrahedral; 5 pairs, trigonal pyramidal; 6 pairs, octahedral.

Sometimes, this geometry is not readily apparent. There are 4 electron pairs around the central oxygen atom in water, *lone* pairs per oxygen atom), and to a first approximation these 4 electron pairs assume the shape of a tetrahedron, which has bond angles of

So the ideal *atoms* ; water is thus described as a bent molecule. How would I describe the geometry of the presumed acidium species in water,

Also see this answer .