Final answer:
The chemical formula for the ionic compound created by element X with 2 valence electrons and element Z with 6 valence electrons is XZ2.
Step-by-step explanation:
The chemical formula for the ionic compound created by element X with 2 valence electrons and element Z with 6 valence electrons is XZ2. This is because element X will donate its 2 valence electrons to element Z, which will then accept them, resulting in the formation of an ionic bond. The number in the subscript indicates the ratio of X to Z atoms in the compound.