What is missing from this list: Hydrogen, ? , Zinc, Carbon, Flourine, Boron, Zirconium, Niobium, Palladium, Yttrium?

May we know the context of where you got this list from? It would seem we need a clue given no one has cracked it thus far. My thoughts so far:

The atomic numbers in sequence are: 1, ?, 30, 6, 9, 5, 40, 41, 46, 39. No matches with the OEIS (Online Encyclopedia of Integer Sequences).

Initials are: H?ZCFBZNPY - no words or anagrams possible

By chemical symbol: H?ZnCFBZrNbPdY - no words or anagrams possible

We have representatives from many different categories of elements (halogens, transition metals, etc.) with no discernible pattern.

Some of the elements are reminiscent of those used in 'YBCO' ceramic superconductors, but that doesn't quite fit the list either.

https://oeis.org/search?q=30%2C+6%2C+9%2C+5%2C+40%2C+41%2C+46%2C+39&language=english&go=Search