Answer:
[tex]\boxed {\boxed {\sf Cobalt, Iron, and \ Copper}}[/tex]
Explanation:
The Stock System states that In a chemical formula or equation, some metals need a roman numeral after their symbol. If a metal has multiple oxidation states, it needs a roman numeral.
Use the Periodic Table to see the oxidation states for each metal.
- Cobalt (Co): +3, +2
- Lithium (Li): +1
- Barium (Ba): +2
- Iron (Fe): +3, +2
- Copper (Cu): +2, +1
- Potassium (K): +1
We can see that cobalt, iron, and copper have more than one oxidation state, so they would require a roman numeral.
