Final answer:
The systematic name for Ni2(SO4)3 is nickel(II) sulfate, indicating that nickel is in the +2 oxidation state.
Step-by-step explanation:
The systematic name for the compound Ni2(SO4)3 involves identifying the cation and the anion, and if necessary, indicating the oxidation state of the cation when it can have more than one possible charge. Nickel can exist in multiple oxidation states, and in this formula, it is in the +2 oxidation state. The sulfate ion, which is a polyatomic ion, has a charge of -2. Since there are three sulfate ions needed to balance the charge of two nickel ions, we deduce that each nickel ion has a +2 charge.
Therefore, the systematic name for Ni2(SO4)3 is nickel(II) sulfate. This uses the Stock system of nomenclature where the Roman numeral indicates the oxidation state of the nickel ion.