Answer:
2+
Step-by-step explanation:
Ions are separated into cations and anions.
Oxidation State
The roman numeral after iron represents the oxidation state. The oxidation state shows the hypothetical charge of an atom. Since iron can have different oxidation states, it needs to be noted using a roman numeral. Iron can either be iron (II) or iron (III), which have a 2+ and 3+ charge, respectively.
Cations
Ions are atoms that have negative or positive charges. Negative ions are called anions, and positive ions are called cations. Atoms that have almost full valence shells (5-7 valence electrons) take electrons and become anions. Atoms that have almost empty valence shells (1-3 valence electrons) lose electrons and become cations.
Iron (II) has 2 valence shell electrons, so it will be a cation. When it bonds, it will lose both valence electrons. Since atoms gain a 1+ charge for every electron it loses, iron (II) will have a 2+ charge.