We arrived from the subatomic world in the atomic world. The macrocosmic world as we experience as our physical environment.
The periodic table:
We know a lot about all these elements. There is no need to further elucidate here on this. It is part of our daily life.
Having said this, we now have indications how to interpret some peculiarities, like the Lanthanides and the fact that the range is limited to somewhat more than 100 elements. Apparently, the heavier nuclei have difficulties to keep the integrity of the nucleus intact under high rotation in three axes. The Lanthanides are maybe reinforcements, and the other heavy elements do not need a lot to trigger degradation.
There is a lot to be studied provided there is scientific interest to do so.