Chemistry of the 5g Elements: Relativistic Calculations on Hexafluorides

Many covalent molecules have central atoms that do not have eight electrons in their Lewis structures. These molecules fall into three categories:

The electron affinity (EA) is the energy change for adding an electron to a gaseous atom to form an anion (negative ion).

Electron configurations and orbital diagrams can be determined by applying the Aufbau principle (each added electron occupies the subshell of lowest energy available), Pauli exclusion principle (no two electrons can have the same set of four quantum numbers), and Hund’s rule of maximum multiplicity (whenever possible, electrons retain unpaired spins in degenerate orbitals).
The relative energies of the subshells determine the order in which atomic orbitals are filled (1s, 2s, 2p, 3s, 3p,...

sp3d and sp3d 2 Hybridization

Lattice Energy 

Overview of VSEPR Theory