Question

Fe2O3 is named iron (III) oxide because it contains

A. 3 oxygen atoms
B. Fe3+ ions
C. 3 iron atoms
D. O3+ ions

Answer 1

Fe2O3 is named iron (III) oxide because it contains Fe3+ ions; the Roman numeral III indicates the +3 oxidation state of iron present in the compound.

Step-by-step explanation:

Fe2O3 is named iron (III) oxide because it contains Fe3+ ions. When naming ionic compounds containing iron, it's necessary to indicate the iron's oxidation state, which is the same as its charge.

Since there are two iron atoms each with a +3 charge to balance the three oxygen atoms each with a -2 charge, the correct answer is B. Fe3+ ions. Iron can form different cations, such as Fe2+ and Fe3+, which, when combined with an anion, result in different compounds. In Fe2O3, iron has lost three electrons to become Fe3+, and this is reflected in the name iron (III) oxide, where the Roman numeral III indicates the +3 oxidation state of iron.