Question

Supply a Stock system name for each of the following binary ionic compounds: (a) \(\mathrm{CoO}\) (b) FeO (c) \(\mathrm{HgO}\) (d) \(\mathrm{SnO}\)

Short answer

(a) Cobalt(II) Oxide; (b) Iron(II) Oxide; (c) Mercury(II) Oxide; (d) Tin(II) Oxide.

Step-by-step solution

Understanding Binary Ionic Compounds

Binary ionic compounds consist of two elements: a metal and a non-metal. In the system of nomenclature, the metal cation is named first and can have multiple oxidation states. These different oxidation states are specified using Roman numerals in the Stock system.

Finding Oxidation States

For each compound, determine the oxidation state of the metal by considering the charge of the anion. Oxygen typically has an oxidation state of -2. Solve for the metal's oxidation state using the formula: \[ ext{Charge of metal} + ext{(Number of oxygens)} imes (-2) = 0 \]

Naming (a) \( \text{CoO} \)

Given that oxygen's oxidation state is -2, the cobalt in \(\text{CoO}\) must have a +2 oxidation state to balance the charge, as shown: \( 2x - 2 = 0 \). Therefore, this compound is named Cobalt(II) Oxide.

Naming (b) \( \text{FeO} \)

For \(\text{FeO}\), with oxygen at -2, the iron must be +2. Solve using: \( 2x - 2 = 0 \), yielding the name Iron(II) Oxide.

Naming (c) \( \text{HgO} \)

In \(\text{HgO}\), mercury must balance -2 from oxygen, thus having a +2 oxidation state: \( 2x - 2 = 0 \). This gives us the name Mercury(II) Oxide.

Naming (d) \( \text{SnO} \)

For \(\text{SnO}\), solve \( 2x - 2 = 0 \) to find tin's oxidation state is +2. The compound name becomes Tin(II) Oxide.

Key concepts

Stock System Nomenclature

The Stock System Nomenclature is a method used to name binary ionic compounds, especially those with metals that can have more than one oxidation state. This system helps avoid ambiguity by clearly indicating the oxidation state of the metal involved in a compound.
To utilize this system:

• The name of the metal is followed by its oxidation state in Roman numerals, enclosed in parentheses.
• The non-metal's name follows the metal's, typically ending in "-ide."
  For example, in the compound \( \text{FeO} \), the iron (Fe) cation gets an oxidation state of +2 to balance the charge from the oxygen anion (-2), thus it is named Iron(II) Oxide.

By including the oxidation state, the Stock System Nomenclature ensures precise and clear communication of chemical compositions.

Oxidation States

Oxidation states, often referred to as oxidation numbers, are essential in understanding chemical reactions and compound balancing. They indicate the degree of oxidation (loss of electrons) of an atom in a chemical compound.
In binary ionic compounds:

• Metal atoms can exhibit various oxidation states, which affect how they form compounds with non-metal atoms.
• The sum of the oxidation states in a neutral compound must equal zero.
  For example, in \( \text{CoO} \), the oxidation state of cobalt is +2, as it needs to balance the -2 charge from oxygen. This is calculated using the equation: \[ \text{Charge of metal} + \text{(Number of oxygens)} \times (-2) = 0 \]

Understanding oxidation states is crucial for correctly naming compounds and predicting chemical behaviors.

Metal and Non-Metal Elements

In binary ionic compounds, the elements involved typically include one metal and one non-metal. This fundamental composition shapes how compounds are structured and named.
Here are the key characteristics:

• Metals are usually positioned on the left side of the periodic table and tend to lose electrons, forming positive ions or cations.
• Non-metals are found on the right side of the periodic table and generally gain electrons, becoming negative ions or anions.
  For instance, in compounds like \( \text{HgO} \), mercury (a metal) forms a cation by losing electrons, while oxygen (a non-metal) forms an anion by gaining electrons.

Recognizing the roles of metal and non-metal elements aids in predicting the formation and properties of binary ionic compounds.