Question

Name these compounds by the Stock System (IUPAC): (a) \(\mathrm{CuCl}_{2}\) (d) \(\mathrm{FeCl}_{3}\) (b) \(\mathrm{FeCl}_{2}\) (e) \(\mathrm{SnF}_{2}\) (c) \(\mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{2}\) (f) \(\mathrm{VPO}_{4}\)

Short answer

The names are: copper(II) chloride, iron(II) chloride, iron(III) chloride, iron(II) nitrate, tin(II) fluoride, and vanadium(III) phosphate.

Step-by-step solution

- Understand the Stock System

The Stock System (IUPAC) names compounds by indicating the oxidation state of the metal as a Roman numeral in parentheses immediately following the metal name.

- Name \(\mathrm{CuCl}_2\)

Determine the oxidation state of Cu in \(\mathrm{CuCl}_2\). Each Cl has a -1 charge, and there are 2 Cl atoms, giving a total charge of -2. Therefore, Cu must have a +2 oxidation state to balance the charges. The name is copper(II) chloride.

- Name \(\mathrm{FeCl}_2\)

Determine the oxidation state of Fe in \(\mathrm{FeCl}_2\). Each Cl has a -1 charge, and there are 2 Cl atoms, giving a total charge of -2. Therefore, Fe must have a +2 oxidation state to balance the charges. The name is iron(II) chloride.

- Name \(\mathrm{FeCl}_3\)

Determine the oxidation state of Fe in \(\mathrm{FeCl}_3\). Each Cl has a -1 charge, and there are 3 Cl atoms, giving a total charge of -3. Therefore, Fe must have a +3 oxidation state to balance the charges. The name is iron(III) chloride.

- Name \(\mathrm{Fe(NO_3)_2}\)

Determine the oxidation state of Fe in \(\mathrm{Fe(NO_3)_2}\). Each \(\mathrm{NO_3}\) has a -1 charge, and there are 2 \(\mathrm{NO_3}\) groups, giving a total charge of -2. Therefore, Fe must have a +2 oxidation state to balance the charges. The name is iron(II) nitrate.

- Name \(\mathrm{SnF}_2\)

Determine the oxidation state of Sn in \(\mathrm{SnF}_2\). Each F has a -1 charge, and there are 2 F atoms, giving a total charge of -2. Therefore, Sn must have a +2 oxidation state to balance the charges. The name is tin(II) fluoride.

- Name \(\mathrm{VPO_4}\)

Determine the oxidation state of V in \(\mathrm{VPO_4}\). \(\mathrm{PO_4}\) has a charge of -3. Therefore, V must have a +3 oxidation state to balance the charges. The name is vanadium(III) phosphate.

Key concepts

Oxidation States

Oxidation states are essential for naming chemical compounds, especially those involving transition metals. The oxidation state of an atom in a compound indicates its degree of oxidation and is denoted as a positive or negative integer. For example, in \(\text{FeCl}_3\), iron (Fe) has an oxidation state of +3 because each chlorine (Cl) has an oxidation state of -1 and there are three chlorines, resulting in Fe balancing the total charge with +3. To determine oxidation states, follow these guidelines:

• Elements in their pure form have an oxidation state of zero (e.g., \(\text{O}_2\) has an oxidation state of 0).
• For ions, the oxidation state is the same as the ion charge (e.g., \(\text{Na}^+\) has an oxidation state of +1).
• In compounds, certain atoms consistently have the same oxidation state (e.g., oxygen is usually -2, and hydrogen is typically +1).
• The sum of oxidation states in a neutral compound must be zero, while in a polyatomic ion, it should equal the ion's charge.

Understanding these principles helps in correctly naming and balancing chemical equations.

IUPAC Naming

The International Union of Pure and Applied Chemistry (IUPAC) system standardizes chemical compound names globally. This system provides a clear and consistent way to name compounds, removing ambiguity. One crucial aspect of IUPAC naming for transition metals is the Stock System. Here’s how it works:

• The metal's name is written first.
• The metal's oxidation state is shown in Roman numerals within parentheses immediately following the metal’s name (e.g., iron(III) chloride).
• The non-metal's name follows, with its ending changed to '-ide' if it’s a simple anion (e.g., chloride for Cl^-, fluoride for F^-).

Using these rules ensures accuracy and uniformity in chemical nomenclature. For instance, \(\text{FeCl}_2\) is named iron(II) chloride because iron has an oxidation state of +2.

Transition Metal Compounds

Transition metals have unique properties making their compounds interesting and essential in chemistry. Because they can possess multiple oxidation states, it's crucial to specify which oxidation state is present in a given compound. For example, iron can form both \(\text{FeCl}_2\) (iron(II) chloride) and \(\text{FeCl}_3\) (iron(III) chloride). This versatility in forming different compounds results in diverse chemical reactivity and applications.

When analyzing such compounds:

• Identify the non-metal and its usual oxidation state.
• Calculate the total negative charge contributed by the non-metals.
• Balance this charge with the appropriate positive oxidation state of the metal to maintain overall neutrality.

Hence, it’s essential to comprehend both the variable oxidation states of transition metals and their influence on compound behavior.