De or het ununennium?

The correct Dutch article is:

het ununennium

Rule Words ending in -um and -ium: usually het. See the rule
Meaning (Dutch) (scheikunde, element) een scheikundig element met het symbool Uue en het atoomnummer 119

How to use ununennium

the ununenniumhet ununennium
this ununenniumdit ununennium
that ununenniumdat ununennium
our ununenniumons ununennium
your ununenniumjouw ununennium
every ununenniumelk ununennium
which ununennium?welk ununennium?
a big ununennium / the big ununenniumeen groot ununennium, het grote ununennium

Meaning, plural, diminutive, pronunciation and translations: WikiWoordenboek (Dutch Wiktionary) (CC BY-SA 4.0). Example sentences: Tatoeba (CC BY 2.0 FR).