Answer:
See below
Step-by-step explanation:
The Roman numerals indicate how many electrons that element can contribute to bonding with a second element that accepts electrons in order to acieve a lower energy state. Cu(II), for example, indicates 2 electrons are available (Copper would lose two electrons and have a charge of +2).
The charge of the metal ion, and therefore the Roman numeral, is determined by looking at the formula of the compound, along with the charge of the anion attached it it. In the case of CuI, the anion is I (Iodine), which has a charge of -1. Copper, Cu, has two possible oxidation states, as noted above. it can have a charge of either +1 or +2. These would be represented by Cu(I) and Cu(II).
The charge of the anion becomes the key in determining the oxidation state of the cation.
For CuI, one iodine bonds with one copper to make CuI. Since the iodine ion has a charge of -1, this means the copper with have a change of +1. This means it's oxidation sate is +1, which is represented by the symbol Cu(I). The correct IUPAC (International Union of Pure and Applied Chemistry) formula would therefore be Cu(I)I.
Another element with more than 1 oxidation state is iron. Iron typically exhibits a charge of either 2+ or 3+. when combined with an ion with a single negative charge such as chlorine, Cl, the two corresponding compound formulas are FeCl2 and FeCl3. The simplest name, “iron chloride,” would be ambiguous, as that simple name would not distinguish between the two possible compounds. In this case, the charge of the metal ion is included as a Roman numeral in parentheses: Fe(II) or Fe(III). These two compounds are named iron(II) chloride and iron(III) chloride, respectively.
Cul _Cu(I)I___Copper(I) iodide__
FeSO4 __Fe(II)SO4__ Iron(II) sulfate
Cu(NO3)2 __Cu(II)(NO3)2__ Copper(II) nitrate
CrCl3 __ Chromium(III) chloride
Pb(CIO)2 Lead(II) dichlorate (or lead(II) perchlorate)
Au₂0 _ Gold(I) oxide
SnF4 _ Tin(IV) fluoride
Sno __ Tin(II) oxide
Ni₂O3 _ Nickle(III) oxide
SnO₂ _ Tin(IV) oxide