Question

Supply the Stock system name for each of the following monoatomic cations: (a) \(\mathrm{Ca}^{2+}\) (b) \(\mathrm{Cd}^{2+}\) (c) \(\mathrm{Co}^{2+}\) (d) \(\mathrm{Cu}^{2+}\)

Short answer

(a) calcium(II), (b) cadmium(II), (c) cobalt(II), (d) copper(II).

Step-by-step solution

Understanding the Stock System

The Stock system is a method of nomenclature for ions that indicates the oxidation state of an element when it can exist in more than one form. The oxidation state is represented by a Roman numeral placed in parentheses right after the name of the element.

Calcium Ion

Identifying the stock name for Ca^{2+} is straightforward. Calcium typically forms only one type of cation carrying a +2 charge. Thus, in the Stock system, the ion is named calcium(II).

Cadmium Ion

For Cd^{2+}, cadmium primarily forms one cation with a +2 charge. Thus, its Stock name is cadmium(II).

Cobalt Ion

Cobalt can exist in multiple oxidation states. For the Co^{2+} ion, it has a +2 charge, and the Stock system name is cobalt(II).

Copper Ion

Copper, similar to cobalt, can have different oxidation states, notably Cu^{+} and Cu^{2+}. For Cu^{2+}, the Stock system name is copper(II).

Key concepts

Oxidation State

Understanding the concept of oxidation states is crucial in the realm of chemistry. Simply put, an oxidation state, also referred to as oxidation number, indicates the degree of oxidation of an atom in a compound. It's essential for identifying the electron exchange process between atoms during reactions. This number can be positive, negative, or zero and signifies how many electrons an atom gains, loses, or shares when forming a compound.

• A positive oxidation state means the atom has lost electrons.
• A negative oxidation state implies gained electrons.
• An oxidation state of zero usually means the atom has equal numbers of gained and lost electrons, often seen in elemental forms.

In the Stock system, the oxidation state helps us name ions correctly, especially those capable of existing in different charged forms. For instance, a copper ion can exhibit oxidation states of +1 or +2, hence the existence of copper(I) and copper(II) ions. Understanding these states assists in predicting chemical behavior and reactions in compounds.

Monoatomic Cations

Monoatomic cations are single-atom ions with a positive charge. They result when an atom loses electrons, making the atom positively charged. These ions are crucial in forming ionic bonds, where the positively charged cations are attracted to negatively charged anions.
Monoatomic cations can have varying charges based on their position in the periodic table.

• Alkali metals like sodium (\(\mathrm{Na}^{+}\)) typically form +1 cations.
• Alkaline earth metals, such as calcium (\(\mathrm{Ca}^{2+}\)), usually form +2 cations.
• Transition metals, like cobalt and copper, can form more than one type of cation, necessitating the need for a systematic naming approach using their oxidation states.

It's essential to understand the charge of these ions because it determines how they interact in chemical reactions. Using the Stock system, we can precisely name these ions, reflecting their oxidation states.

Chemical Nomenclature

Chemical nomenclature is the systematic method of naming chemical substances. It is essential for scientists and students alike to communicate complex chemical information effectively. One of the critical systems in chemical nomenclature is the Stock system, used primarily for naming inorganic compounds and their monoatomic ions.
This system brings clarity, particularly with transition metals, which can exist in multiple oxidation states. By employing Roman numerals to denote the oxidation state right after the element's name, the Stock system eliminates ambiguity.
For example:

• \(\mathrm{Co}^{2+}\) is known as cobalt(II), clearly indicating an oxidation state of +2.
• \(\mathrm{Cu}^{2+}\) is referred to as copper(II), separating it from copper(I) with a +1 charge.
This precision in naming allows chemists to convey important details about the compounds. Such information includes their potential reactivity and properties, leading to a better understanding and application of chemical compounds in various industries and research fields.