Since the s and p orbitals are closer to the nucleus, they take a bigger portion of the electric charge of the nucleus on themselves ("shield" it). This leaves less charge for attraction of the remaining electrons, whose orbitals therefore expand, making them easier to pull from the nucleus. This is the indirect relativistic effect. As a result of the combination of the direct and indirect relativistic effects, the Hs ion, compared to the neutral atom, lacks a 6d electron, rather than a 7s electron. In comparison, Os lacks a 6s electron compared to the neutral atom. The ionic radius (in oxidation state +8) of hassium is greater than that of osmium because of the relativistic expansion of the 6p orbitals, which are the outermost orbitals for an Hs ion (although in practice such highly charged ions would be too polarized in chemical environments to have much reality).
Since the s and p orbitals are closer to the nucleus, they take a bigger portion of the electric charge of the nucleus on themselves ("shield" it). This leaves less charge for attraction of the remaining electrons, whose orbitals therefore expand, making them easier to pull from the nucleus. This is the indirect relativistic effect. As a result of the combination of the direct and indirect relativistic effects, the Hs ion compared to the neutral atom, lacks a 6d electron, rather than a 7s electron In comparison Os lacks a 6s electron compared to the neutral atom. The ionic radius (in oxidation state +8) of hassium is greater than that of osmium because of the relativistic expansion of the 6p orbitals, which are the outermost orbitals for an Hs ion (although in practice such highly charged ions would be too polarized in chemical environments to have much reality).