«This means that traditional descriptions of the electronic structure of actinide elements are often of a qualitative nature — but this is precisely the area where quantitative models are needed because our understanding of core chemical concepts become increasingly nebulous at the foot of the periodic table.» (sciencedaily.com)
Let's consider some traditional descriptions, beginning with perhaps the most authoritative of all such, that given by the Fathers of the Council of Trent, in the 22nd Session: (faith.org.uk)