Periodic tableUploader: Shajora 2 month ago Subscribe 6
For example, the f-electron counts for the first five f-block elements are La 0, Ce 1, Pr 3, Nd 4 and Pm 5. There are currently several competing theoretical models for the placement of the elements of atomic number less than or equal to Top of the charts". The chemistry of the transition elements. The Atom in the History of Human Thought.