The name of the compound Ni(NO3)2 is nickel(II) nitrate. The Roman numeral II after nitrate refers to a nickel ion that contains a charge of plus two. Different ions of nickel can contain a different number of charges.
The name of the compound can be determined by isolating each element in the formula and determining the charges. The symbol Ni represents nickel, while the symbol N represents nitrogen and the symbol O represents oxygen. Combined together, the combination of one nitrogen atom and three oxygen atoms constitutes the compound nitrate. The charge of the nickel can be determined by looking at the subscript after the nitrate.