Problem 25 - Chemistry: An Atoms-Focused Approach

Question

Consider a mythical element \(\mathrm{X},\) which forms two oxoanions: \(\mathrm{XO}_{2}^{2-}\) and \(\mathrm{XO}_{3}^{2-} .\) Which of the two has a name that ends in -ite?

Step-by-Step Solution

Answer

Answer: \(\mathrm{XO}_{2}^{2-}\)

Step 1: Understand the naming conventions of oxoanions

There are two suffixes used to name oxoanions, -ite and -ate. The -ite suffix is used for an oxoanion with fewer oxygen atoms, while the -ate suffix is used for an oxoanion with more oxygen atoms bonded to the central atom.

Step 2: Identify the oxoanions and count their oxygen atoms

We have two oxoanions given in the problem: \(\mathrm{XO}_{2}^{2-}\) and \(\mathrm{XO}_{3}^{2-}\). Count the number of oxygen atoms for each: 1. \(\mathrm{XO}_{2}^{2-}\): There are 2 oxygen atoms. 2. \(\mathrm{XO}_{3}^{2-}\): There are 3 oxygen atoms.

Step 3: Determine which oxoanion's name ends in -ite

Based on the naming conventions mentioned in Step 1, the oxoanion with fewer oxygen atoms will have a name ending in -ite. Since \(\mathrm{XO}_{2}^{2-}\) has fewer oxygen atoms than \(\mathrm{XO}_{3}^{2-}\), the name of \(\mathrm{XO}_{2}^{2-}\) will end with -ite.

Key Concepts

Naming Conventions

Naming conventions for oxoanions are essential as they provide a systematic way to name compounds, which helps in identifying their structure and composition. Oxoanions are negatively charged ions that consist of oxygen atoms bonded to a central element, often a nonmetal or transition metal. To effectively name oxoanions, we use specific suffixes that help in distinguishing between different forms that an element might take when bonded with oxygen.

These suffixes include:

• "-ite" which is used for oxoanions with fewer oxygen atoms.
• "-ate" which applies to oxoanions with more oxygen atoms.

This naming system helps in maintaining consistency and reducing confusion, especially when dealing with elements that can form multiple oxoanions.
So, when you hear the name of an oxoanion with the suffix "-ite," you should think of it as the simpler version with fewer oxygen atoms compared to its "-ate" counterpart.

Oxygen Atoms Counting

Counting oxygen atoms is a fundamental step in determining the correct name for oxoanions. This process involves analyzing the chemical formula of the ion to assess how many oxygen atoms are attached to the central atom.

Using our example from the exercise:

• In \[\mathrm{XO}_{2}^{2-}\], the subscript 2 indicates that there are 2 oxygen atoms.
• For \[\mathrm{XO}_{3}^{2-}\], the subscript 3 means there are 3 oxygen atoms.

Counting these atoms correctly is crucial as it directly influences the choice of suffix, "-ite" or "-ate," in the naming process.

It also serves as a basis for comparison, which helps to identify which oxoanion is considered to have more or fewer oxygen atoms than another, essential for applying the naming conventions effectively.

Suffixes -ite and -ate

The suffixes "-ite" and "-ate" play a pivotal role in the naming of oxoanions. When we talk about these suffixes, we're focusing on the oxygen content in the compound. The suffix chosen indicates the relative number of oxygen atoms bonded to the element in question.

• "-ite" Suffix: This suffix signals that the oxoanion has fewer oxygen atoms than other possible versions of the oxoanions containing the same element. For instance, in our exercise example, \[\mathrm{XO}_{2}^{2-}\] ends with "-ite" because it has fewer oxygen atoms (2) compared to its counterpart.
• "-ate" Suffix: It is used when there is a higher number of oxygen atoms present in the oxoanion. In the given problem, \[\mathrm{XO}_{3}^{2-}\] would end with "-ate," indicating 3 oxygen atoms, the greater number of the two possible oxoanions.

Understanding when to use "-ite" versus "-ate" can help in recognizing the chemical and environmental characteristics of an oxoanion, as these relate to oxidation states and stability. Hence, these suffixes are not just about naming, but also about the chemical behavior and properties of the compounds.