Dear User,
s,p,d,f electronic configuration is the orbital configuration. Atomic orbitals are the regions where there is maximum probability of finding electrons. These orbitals have different shape.Each shell contains sub-shells and these sub-shells are denoted as s,p,d,f. The energies of the various sub shells in the same shell are in the order of s<p<d<f(increasing order). This means that while filling up electrons, electron first go to the s orbital, than p, than d and than f.