Radianesson

Radianesson (Rsn), or Unhexoctium, is the 168th element of periodic table. It is also the 50th and last element of period 8, which is the final normal period of a Periodic Table in our cosmology.

It is not a noble gas, but a plasma due to being extremely radiant, as radiation heats this element up as the period increases. We don't know why this element in plasma state is hyperstable, but we only know that it is indirectly caused of a lot of strong forces. This plasma glows a really bright shade of yellow, regardless of isotopes.

Due to being plasma, this is the last radioactive element before biradioactivity begins at element 171. It is also the most radioactive element before biradioactivity begins.

Radianesson-503
This isotope doesn't exist, as trying to form Radianesson-503 always leads into different isotopes of couple smaller elements.

Radianesson-504
Radianesson-504 is the most stable isotope of this element due to a natural phenomenon of red hypergiant stars and probably, neutron stars. You can find it at the inner core.

Radianesson-504 decays into a lot of isotopes, consisting with mostly period-5 elements and many electrons, making it the most efficient power source for Penrose spheres on neutron stars. Trying to build a Penrose sphere on hypergiants will only gather hydrogen for less power.

Radianesson-505
Radianesson-505 is still hyperstable, but 25% less efficient than Radianesson-504. It is frequently appeared in stars during the late hypergiant phase. When decayed, it will split into isotopes and a lot of electrons, but 25% less than Radianesson-504.

After the late hypergiant phase, it will explode like a hypernova, and due to being too massive, it will become a black hole.

Radianesson-506
Radianesson-506 is the least stable isotope, with a lifespan of 2.31 picoseconds, when trying to synthesize it. Although, during the hypernova phase, black holes frequently emit plasma gas out of poles, which all consists with mostly Radianesson-506 that is stable.

1 day after the formation, Radianesson-506 will become Unhexennium-505 by neutron decay, although this anomaly causing this is unknown. Then, Unhexennium will instantaneously decay into smaller isotopes, because 9th-level electron shells are too unstable to sustain.