VSEPR THEROY

Question 1

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Answer 1

The valence shell electron pair repulsion theory (VSEPR) predicts the shape and bond angles of molecules
Electrons are negatively charged and will repel other electrons when close to each other
In a molecule, the bonding pair of electrons will repel other electrons around the central atom forcing the molecule to adopt a shape in which these repulsive forces are minimised
When determining the shape and bond angles of a molecule, the following VSEPR rules should be considered:
Valence shell electrons are those electrons that are found in the outer shell
Electron pairs repel each other as they have similar charges
Lone pair electrons repel each other more than bonded pairs
Repulsion between multiple and single bonds is treated the same as for repulsion between single bonds
Repulsion between pairs of double bonds are greater
The most stable shape is adopted to minimize the repulsion forces
Different types of electron pairs have different repulsive forces
Lone pairs of electrons have a more concentrated electron charge cloud than bonding pairs of electrons
The cloud charges are wider and closer to the central atom’s nucleus
The order of repulsion is therefore: lone pair – lone pair > lone pair – bond pair > bond pair – bond pair