Question

why do most of the elements occur as oxides or sulphide​

Answer 1

the thing is that these elements have a greater capacity to combine and form compounds.

it all depends on the valency.

you don't usually see xenon compounds in daily life cos, they are rare because xenon is a noble gas and does not form compounds at stp(standard temperature and pressure).

but oxides and sulphides form compounds at stp thus most elements combine with them.

but there is one more element that crosses the line. it is carbon, carbon forms so many compounds that it is greater than all the elements compound= more that 10 million.

hope it helps

and answered your question.

bye!