Answer:
Step-by-step explanation:
The correct description is Co⁺².
The chemical symbol Co is the symbol for cobalt element.
The superscript +2 to the right of the chemical symbol means that the oxidation state of the species is +2. That means that it has a positive charge of 2. Therefore, the neutral atom of cobalt (O) has released to electrons.
As per IUPAC rule you mention the absolute value of the oxidation number with a Roman number in parenthesis, immediately after the name of the element. So, the corresponding Roman number is II, and you must not leave a blank space between the left parenthesis and the name of the ion.
So, the correct name is cobalt(II) ion.