The compound FeCl3 is made of
A. three molecules of iron chloride.
B. one atom of iron and three atoms of carbon.
C. one atom of iron and three atoms of chlorine.
D. two atoms of iodine, one atom of iron, and one atom of carbon.
The Correct Answer and Explanation is:
The correct answer is:
C. one atom of iron and three atoms of chlorine.
Explanation:
The chemical formula FeCl₃ represents a compound composed of one atom of iron (Fe) and three atoms of chlorine (Cl). In this formula, Fe stands for iron, a transition metal, and Cl represents chlorine, a halogen. The subscript “3” next to Cl indicates that there are three chlorine atoms bonded to a single iron atom.
Understanding Chemical Formulas:
Chemical formulas convey information about the composition of compounds by showing which elements are present and in what proportions. In FeCl₃, each element symbol (Fe and Cl) is associated with a subscript that specifies the number of atoms of that element. If there’s no subscript after an element symbol, it means there is only one atom of that element in the molecule. Therefore, Fe without a subscript indicates one iron atom, while Cl₃ means there are three chlorine atoms.
Bonding in FeCl₃:
FeCl₃ is an ionic compound because it forms through the transfer of electrons between iron and chlorine atoms. Iron (Fe) in this compound has a +3 oxidation state, meaning it has lost three electrons. Chlorine (Cl) atoms each have a -1 oxidation state, meaning they have gained an electron. The iron ion (Fe³⁺) attracts three chloride ions (Cl⁻), forming a stable compound through ionic bonds.
Why Other Options Are Incorrect:
- Option A is incorrect because FeCl₃ is a single molecule with one iron atom and three chlorine atoms, not three separate molecules.
- Option B is incorrect because there is no carbon in FeCl₃.
- Option D is incorrect because there are no atoms of iodine or carbon in FeCl₃.
Understanding the correct composition of FeCl₃ is essential in chemistry as it reveals how elements combine to form compounds, emphasizing the role of atomic ratios in creating distinct substances.