Yes. helium is found in its elemental form. it is chemically inert as it has completely filled orbitals.
Helium has completely filled orbitals. hence it is chemically inert (non reactive) and is found in its pure elemental form.
Helium does not combine with other elements and pure helium will exist by itself as elemental helium.
Technetium is found in both in a compound and pure forms
It is a compound
Yes,it is a pure substance but can be mixed with other gases. Like a fart. Har har har
Helium found in atmosphere will have other gases as impurities. But it can be isolated by suitable method (generally by adsorption of gases) to get pure helium.
Calcium is never found in its elemental form in nature.
Pure helium is made of elemental helium only and is a gas at STP. It will not have air.
Sulfur is found both "pure" (elemental Sulfur)or as an ore(sulfur compounds). It occurs commonly in either form.
In atmosphere, helium is found as a mixture along with other gases. But this helium can be isolated and obtained in pure form by suitable techniques.
Helium is used as it is/pure. Helium is an inert gas and does not form part of compounds.
In nature, titanium is always found as a compound, not as a pure metal. Titanium is highly reactive (although less reactive alloys can be made from it).