Out of these 3 elements which gases could be made? Hydrogen, Iodine, and Oxygen.?

Question

They must be real gases existing on earth or in stellar clouds.

Answer 1

HI, if its heated a little, H2, I2, if heated, O2, H2O, if its heated just a teeny bit

Answer 2

Depends what you mean by "gas": in interstellar clouds, radicals may be as important to astronomers as molecules. E.G. H20 or water vapor exists, but H+ and OH- may be more evident.
Some molecules that might be found:
H2 (unionized hydrogen, perhaps the most common substance in universe), 02, HI (hydrogen iodide), H20
Some radicals that may be found:
H+, OH-, H3O+
Iodine is rarer in interstellar clouds than on Earth, so not many iodine compounds are likely to be found.

Answer 3

definetely HI