They didn't react with anything to form compounds.
Their oxidation number of 0 prevents the noble gases from forming compounds readily. All noble gases have the maximum number of electrons possible in their outer shell (2 for Helium, 8 for all others), making them stable.
Explain what the term "halogen" means and why they have this name, and which halogens exist as a solid, a liquid, and a gas at room temperature.
The term "halogen" means "salt-former" and compounds containing halogens are called "salts". All halogens have 7 electrons in their outer shells, giving them an oxidation number of -1. The halogens exist, at room temperature, in all three states of matter: Solid- Iodine, Astatine. Liquid- Bromine. Gas- Fluorine, Chlorine.
