Elements Wiki
Register
Advertisement

Eka-superactinide is an obsolete term which does not have much meaning. By the time an element's atomic number is big enough to put it among "eka-superactinides", its electron structure cannot be predicted by extrapolating from trends observed in smaller elements. Thus, so-called "eka-superactinide" elements can't really be called that.

The term itself derives from periodic structure. Superactinides are eighth period, eka-superactinides ninth.

It is worth noting that the term "superheavy elements" refers to the band stabilized against fission by neutron shell closure at N = 184. Nuclides stabilized against fission by shell closures at N = 228, 258, 308, or 318 are a different group in terms of our state of understanding and interest. Even if nuclides in the vicinity of 354Ubh were classed as "superheavy", they would be around 50 protons shy of Usp, the smallest possible eka-superactinide. Eka-superactinides have nothing to do with superheavy elements.

Advertisement