Topic One: Shapes of Molecules
Valence Electron Pair Repulsion Theory (VSEPR)
Regions of e- density (-, =, 3) will repel each other to achieve maximum separation. This minimises the
repulsive forces.
AXE ‘Configuration’
A – central atom (there is one)
X – other atoms attached to central atom
E – extra/leftover regions of electron density on the central atom
Methane
AX4E0 is tetrahedral
NH3
AX3E1 is trigonal