* 91 Pa : 5f2(3H4) 6d 7s2* 92 U : 5f3(4Io9/2) 6d 7s2* 93 Np : 5f4(5I4) 6d 7s2* 103 Lr : 5f14 7s2 7p1 question-marked* 104 Rf : 5f14 6d2 7s2 question-marked=== CRC ===* David R. Lide (ed), "CRC Handbook of Chemistry and Physics, 84th Edition", online version.
*91 Pa : 5f2(3H4) 6d 7s2*92 U : 5f3(4Io9/2) 6d 7s2*93 Np : 5f4(5I4) 6d 7s2*103 Lr : 5f14 7s2 7p1 question-marked*104 Rf : 5f14 6d2 7s2 question-marked===CRC===*David R. Lide (ed), "CRC Handbook of Chemistry and Physics, 84th Edition", online version.