Final answer:
The elements least likely to react with other elements are known as Noble Gases, due to their complete valence electrons which make them very stable and unreactive.
Step-by-step explanation:
The elements least likely to react with other elements are in a column on the Periodic Table known as the Noble Gases. This group of elements, which includes Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rn) possess characteristics that make them extremely unreactive. Chief among these is their full set of valence electrons, which results in a high level of stability and a lack of tendency to form compounds with other elements.
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