4dxy electron orbital, illustration. 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 4dxy orbital is made up of eight lobes centred on the nucleus. The orbital is seen transparent at middle to show the axes of symmetry and the planar nodes and radial node can be seen at right. Nodes are the regions in an atom with zero electron density and where the electron is least likely to exist. For the 4dxy electron orbital, 4 indicates that it is the fourth energy level, and d indicates that the orbital is shaped like a four leaf clover (except the dz2 orbital), and xy indicates the orientation of the orbital is in the xy-plane. The 4dxy orbital can accommodate up to 2 electrons. It is part of the 4d shell, which contains five orbitals in total. The 4d orbitals are part of the 4 shell, which also contains one spherical 4s orbital and three bi-lobed 4p orbitals, both at a lower energy, and seven lobed 4f orbitals at a higher energy level (not seen).