Summary: KEY CONCEPTS: A=represents the CENTRAL ATOM X=represents the number of surrounding atoms E=represents the number of unshared electrons surrounding the CENTRAL ATOM 2 Regions of High Density Electrons AX2 - Linear 3 Regions of High Density Electrons AX3 = trigonal planar AX2E = Bent 4 Regions of High Density Electrons AX4 = tetrahedral AX3E = Trigonal pyramidal AX2E2 = Bent 5 Regions of High Density Electrons AX5 = Trigonal bipyramidal AX4E = Seesaw AX3E2 = T-shaped AX2E3 = Linear 6 Regions of High Density Electrons AX6 = octahedral AX5E = Square pyramidal AX4E2 = Square planar
