Governmentium

A major research institution has recently announced the discovery of the
heaviest element yet known to science.
The new element has been named Governmentium.  Governmentium (Gv) has one
neutron, 25 assistant neutrons, 88 deputy neutrons, and 198 assistant deputy
neutrons, giving it an atomic mass of 312.
These 312 particles are held together by forces [...]