A Periodicverse is a Universe, where only one element from the periodic table of elements is allowed to exist. These Universes are rare and unstable.
Star formation, planetary formation and anything really ceases to exist. Since the laws of physics are bent to such a degree, that the only stable atomic structure is that of a singular model, many other things are also deformed conceptually, and thus these Universes, whilst still bearing known concepts, can be very wild.
There exist 1,447 Periodicverses, 1,425 of which are located inside of our Metaverse, whilst 21 others are located in the Intermetoidal Void, which is the void between Metaverses, and only 1 is inside of another Archverse, that being a rogue Multiverse.
Periodicverses are spread out randomly like white noise, it seems that their property is meerly a "genetic mutation" of intertwining laws of physics upon the formation of Multiverses.
Periodicverses can be seperated into 5 major groups:
There are many minor groups, as the majority of the periodic table has at least 1 Periodicverse associated with it, but most of the Periodicverses with elements of high proton counts don't even have any atoms, due to the fact that every single other atom is unstable, so for the stable atom to form, its particles must go through a very specific process to immediately arrange themselves in the correct order.
An H-Star is a star composed primarily out of an extremely hot glowing mercury-like substance.
H-Stars are very rare, verses which allow only mercury to be formed, can create these, and even then, there's a tiny chance of there being one.
So far, only 151,812 H-Stars exist in all Periodicverses.
Their size ranges from 40,000 - 200,000 km.