The elements least likely to react with other elements are the noble gases, chemically inert elements in group 8 of the periodic table and so cannot react with other elements.
The noble gases are:-
Helium
Neon
Argon
Krypton
Xenon
Radon
The metallic elements Gold and Tantalum are also very non reactive but it does react under very high pressure or temperature.
Elements least likely to react with other elements are in the noble gases column. They have full valence electron shells, making them stable and unreactive.
Argon is the least likely to react with other elements because it is a noble gas and has a full outer electron shell, making it stable and unreactive.
Krypton (Kr) is the Group 18 element most likely to form a compound with fluorine because it has the highest electronegativity and more tendency to react with other elements, compared to xenon (Xe) and argon (Ar).
Elements in the same group as sodium (Group 1) on the periodic table, such as potassium, lithium, and cesium, would have similar chemical behavior. These elements all have one valence electron, which makes them highly reactive and likely to form positive ions.
Noble gases, such as helium, neon, and argon, will never react with other elements. They have a full outer electron shell, making them stable and unreactive.