Anything labeled
BLACK is Ulta Top Secret Umbra -
COSMIC Security Clearance relative.
To say the missing Elements are
BLACK means that They were developed or discovered in
BLACK Programs, usually VIA nefarious methods, and then kept hidden from Public Scrutiny.
That said, I can tell You of another Element that is not on the Periodic Table currently - That is
H³ or
Tri-Hydrogen (
IIRC). This can only be created in the Zero Gravity Enviroment of Space and is currently made on the Military ISS. Not the Civilian ISS.
Apparently -
H³ is used in the manufacture of
Anti-matter...