d electron orbitals 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 Four of the five d orbitals are made up of four trilobed lobes centred on the nucleus The orbital at top comprises two tri lobed lobes with a concentric pair of equatorial rings The shell also contains one spherical s orbital and three lobed p orbitals both at a lower energy and seven lobed f orbitals at a higher energy level not seen The d shells are partially full in the third row of transition metals which typically form coloured compounds as electron transitions between d orbitals absorb some visible wavelengths of light