chemical formula regarding M.9

[Noh_Jasmine_1J]

hi, I just had a question for M.9, which asks for us to write the net ionic equation for the reaction: copper(II) nitrate reacts with sodium hydroxide to produce a precipitate of light blue copper(II) hydroxide. what do the Roman numerals mean and how does NaNO3 appear on the products side out of nowhere?

[aisteles1G]

The roman numerals stand for the charge on the atom, so copper (ll) Nitrate means that the copper has to have a +2 charge so the net charge would be zero on the molecule. Cu(NO3)2 would be written out Copper (ll) Nitrate. The rule is that for cations that can have multiple charges, you use roman numerals after the first element in parenthesis.

[Krisdylle Repollo 4H]

The roman numerals in Copper (II) just indicate the charge of the metal. Another way to see it is CU2+. We use roman numerals because some metals have more than one ion. In the case of copper, there are two; copper (I) (cuprous) and copper (II) (cupric).