Final answer:
Element X is likely a halogen from Group 17 of the periodic table, as it forms compounds CuX and CuX₂ indicating its ability to balance copper's 1+ and 2+ oxidation states.
Step-by-step explanation:
Element X reacts with copper to form the compounds CuX and CuX₂. Since copper can form cations with either a 1+ or 2+ charge, the presence of both CuX and CuX₂ indicates that element X must be able to balance both charges. The periodicity of the representative elements helps determine the group in which element X is found. Compounds where oxidation states can vary, such as copper exhibiting oxidation states of +1 and +2, are not uncommon among transition metals, which are found in groups 3-11 of the periodic table.
Considering that element X must react to form both 1+ and 2+ charges, it suggests that X is a halogen from Group 17, which includes elements like chlorine, bromine, and iodine capable of forming -1 charges to balance the 1+ charge of Cu in CuX and -2 charges (as in diatomic form, X₂) to balance the 2+ charge of Cu in CuX₂.