His table leaves a hole under yttrium and has three 15-element rows in an f-block floating beneath the main table. Nor is he so constrained by atomic numbers. For instance, element 164 is followed ...

Actinides and lanthanides, the f-block elements, are used in a wide variety of fields including telecommunications, medicine, imaging, sensors, energy, catalysis, and data storage. However ...

To account for this, most periodic tables hive off the elements making up this f-block, putting it below the table, leaving a gap in group 3. Fair enough. But there is debate over which of the ...