Final answer:
Iron (II) sulfide has the chemical formula FeS, which corresponds to option A) FeS. This compound includes one iron atom with a 2+ charge and one sulfur atom, creating an iron to sulfur ratio of 1:1.
Step-by-step explanation:
The composition of iron (II) sulfide is represented by the chemical formula FeS. This compound consists of one iron (Fe) atom with a 2+ oxidation state (denoted by the Roman numeral II) and one sulfur (S) atom. The correct choice from the provided options is A) FeS. This is because the chemical name for the compound reflects the oxidation state of the iron ion: 'iron(II)' implies that iron has a 2+ charge, and when combined with sulfur, it forms a compound with a 1:1 ratio of iron to sulfur atoms, giving the formula FeS. This is different from iron(III) sulfide which has a formula of Fe2S3, reflecting the 3+ oxidation state of iron in that compound.