4f electron orbitals, cubic set, computer model. An electron orbital is a region around an atomic nucleus (not seen) in which one or a pair of electrons is most likely to exist. The 4f orbitals are unusual in that there are two ways to represent the orbital shapes. In the cubic set, the bottom four orbitals are eight-lobed. The three upper orbitals have lobes with encircling cones. The general set is shown in image A152/144. The 4f orbitals are partially filled in the Lanthanide metals.