Why are s & p sublevels considered so important? Why are these the only electrons considered in the octet rule

Answer 1

s- and p- sublevels are only considered important in the Lewis theory of the octet rule and the two-electron bond. For elements that have d-sublevels, the octet rule quickly breaks down. Sulfur hexafluoride (SF6) and osmium tetraoxide (OsO4) for example. For these compounds,one must use valence bond theory, orbital hybridization, and quantum mechanical calculations.