Question

Iron forms both $2+$ and $3+$ cations. Write formulas for the oxide, sulfide, and chloride compound of each iron cation, and give the name of each compound in both the nomenclature method that uses Roman numerals to specify the charge of the cation and the -ous/-ic notation.

Short answer

The following compounds and their names are: 1. FeO - Iron(II) Oxide / Ferrous Oxide 2. FeS - Iron(II) Sulfide / Ferrous Sulfide 3. FeCl2 - Iron(II) Chloride / Ferrous Chloride 4. Fe2O3 - Iron(III) Oxide / Ferric Oxide 5. Fe2S3 - Iron(III) Sulfide / Ferric Sulfide 6. FeCl3 - Iron(III) Chloride / Ferric Chloride

Step-by-step solution

Write formulas for the iron(II) compounds

Iron(II) has a 2+ charge, denoted as Fe(2+). We will now combine it with oxide (O(2-)), sulfide (S(2-)), and chloride (Cl(-)). 1. Iron(II) oxide: Fe(2+) + O(2-) -> FeO 2. Iron(II) sulfide: Fe(2+) + S(2-) -> FeS 3. Iron(II) chloride: Fe(2+) + 2Cl(-) -> FeCl2

Write formulas for the iron(III) compounds

Iron(III) has a 3+ charge, denoted as Fe(3+). We will now combine it with oxide (O(2-)), sulfide (S(2-)), and chloride (Cl(-)). 1. Iron(III) oxide: 2Fe(3+) + 3O(2-) -> Fe2O3 2. Iron(III) sulfide: 2Fe(3+) + 3S(2-) -> Fe2S3 3. Iron(III) chloride: Fe(3+) + 3Cl(-) -> FeCl3

Name the compounds using Roman numerals

Here, we'll provide the names of the compounds using Roman numerals to specify the charge of the cation. 1. Iron(II) oxide: Iron(II) Oxide 2. Iron(II) sulfide: Iron(II) Sulfide 3. Iron(II) chloride: Iron(II) Chloride 4. Iron(III) oxide: Iron(III) Oxide 5. Iron(III) sulfide: Iron(III) Sulfide 6. Iron(III) chloride: Iron(III) Chloride

Name the compounds using -ous/-ic notation

Now we'll provide the names of the compounds using the -ous/-ic notation. 1. Iron(II) oxide: Ferrous Oxide 2. Iron(II) sulfide: Ferrous Sulfide 3. Iron(II) chloride: Ferrous Chloride 4. Iron(III) oxide: Ferric Oxide 5. Iron(III) sulfide: Ferric Sulfide 6. Iron(III) chloride: Ferric Chloride In summary, we have the following compounds and their names: 1. FeO - Iron(II) Oxide / Ferrous Oxide 2. FeS - Iron(II) Sulfide / Ferrous Sulfide 3. FeCl2 - Iron(II) Chloride / Ferrous Chloride 4. Fe2O3 - Iron(III) Oxide / Ferric Oxide 5. Fe2S3 - Iron(III) Sulfide / Ferric Sulfide 6. FeCl3 - Iron(III) Chloride / Ferric Chloride

Key concepts

Chemical Formulas

Understanding chemical formulas is vital for mastering chemistry. They represent the types and amounts of atoms in a compound. For example, take iron compounds: when iron (Fe) bonds with oxygen (O) to form iron(II) oxide, the formula is FeO. This indicates a one-to-one ratio of iron to oxygen atoms. Similarly, iron(III) chloride has a chemical formula of FeCl3, showing one iron atom for every three chlorine atoms.

Learning the correct method to write these formulas involves identifying the charge of the cations and anions involved and ensuring that the compound is electrically neutral. In iron(II) sulfide (FeS), the iron cation Fe(2+) pairs with sulfide anion S(2-) to form a neutral compound without needing to alter the ratio, as their charges balance each other out. Recognizing these patterns helps with predicting the formulas of new compounds, thus making chemistry much more understandable.

Transition Metal Cations

Transition metals such as iron (Fe) can form cations with different charges, leading to the formation of various compounds. Iron typically forms cations with a charge of 2+ (iron(II)) or 3+ (iron(III)). These varying charges affect how transition metals bond with anions. For instance, iron(II) pairs with two chloride anions (Cl-) to create iron(II) chloride (FeCl2), since the 2+ charge of iron is balanced by two 1- charges of the chloride ions.

To grasp this effectively, remember that the goal is to balance the overall charge. If the metal cation and the non-metal anion have different charges, their quantities in the compound adjust accordingly. This understanding is crucial when studying transition metals, as it leads to accurate predictions of chemical formulas and compound structures.

Oxidation States Naming

The oxidation state of a transition metal in a compound is indicated in its name in two primary ways - using either the Roman numeral system or the -ous/-ic suffix system. With the Roman numeral system, the oxidation state is specified in parentheses after the metal's name, such as iron(II) in 'Iron(II) oxide'. It clearly denotes the fact that iron has a +2 charge in the compound.

In the -ous/-ic system, the lower of the two common oxidation states uses the -ous suffix, while the higher state uses the -ic suffix. Thus, 'Iron(II) oxide' can also be called 'ferrous oxide', and 'Iron(III) chloride' becomes 'ferric chloride’. This traditional method is particularly useful for metals with two common oxidation states. Regardless of the naming convention used, understanding the actual charge of the cation is fundamental to both writing and naming chemical compounds correctly.