How do non-metals occur in nature? How are they extracted/isolated from their natural resources?

Some non-metals like inert gases (He, Ne, Ar, Kr, Xe) occur free in nature, whereas some occur in both free and combined states e.g., oxygen, hydrogen, nitrogen, halogens and carbon etc.
Non-metals in general are extracted from their
natural resources by any of the following methods:

(i) By the reduction of oxides and halides.
(ii) By electrolyte reduction of salts, e.g., Cl₂ by electrolytic reduction of conc. NaCl solution.
(iii) By the thermal decomposition of their hydrides.