Answer:
Discrete atoms
Argon
Molecules
Bromine
Nitrogen
Fluorine
Explanation:
The existence of substances in the elemental form depends on the nature of the substance.
Argon is a noble gas hence it seldom participates in chemical combination therefore it exists as discrete molecules in elemental form.
Bromine, fluorine and nitrogen all exist as diatomic gases because they combine readily with each other to form elemental molecules. An elemental molecule is a molecule composed of the atoms of the same element.