Problem 125 - Chemistry The Molecular Science

Question

One way to solve problems is to find an analogy between what you know and what you need to determine. For example, if you know that the formula of magnesium oxide is \(\mathrm{MgO}\), and that sulfur is in Group \(6 \mathrm{~A}\) along with oxygen, by analogy the formula of magnesium sulfide is MgS. By analogy with sulfur or phosphorus compounds, name these compounds: (a) \(\mathrm{Na}_{2} \mathrm{SeO}_{3}\) (b) \(\mathrm{AlSbO}_{4}\) (c) \(\mathrm{K}_{3} \mathrm{AsO}_{4}\) (d) \(\mathrm{Ag}_{2} \mathrm{TeO}_{4}\)

Step-by-Step Solution

Answer

(a) Sodium Selenite, (b) Aluminum Antimonate, (c) Potassium Arsenate, (d) Silver Tellurate.

Step 1: Understand Elemental Groups

Elements in the same group of the periodic table often exhibit similar chemical properties and behave analogously in compound formation. In this exercise, we'll use our understanding of these group similarities to name compounds properly.

Step 2: Na2SeO3 - Selenium's Position and Analogous Naming

Selenium (\(\mathrm{Se}\)) is in the same group as sulfur, Group 16. Therefore \(\mathrm{Na}_2\mathrm{SeO}_3\) is analogous to \(\mathrm{Na}_2\mathrm{SO}_3\), which is sodium sulfite. Hence, \(\mathrm{Na}_2\mathrm{SeO}_3\) is named Sodium Selenite.

Step 3: AlSbO4 - Group Understanding of Sb

Antimony (\(\mathrm{Sb}\)) is in Group 15, along with phosphorus. Analogously, since \(\mathrm{PO}_4^{3-}\) is known as phosphate, \(\mathrm{SbO}_4^{3-}\) will be referred to as antimonate. Thus, \(\mathrm{AlSbO}_4\) is named Aluminum Antimonate.

Step 4: K3AsO4 - Arsenic's Analogy with Phosphorus

Arsenic (\(\mathrm{As}\)) is also in Group 15, like phosphorus. The compound \(\mathrm{K}_3\mathrm{PO}_4\) is potassium phosphate; hence, \(\mathrm{K}_3\mathrm{AsO}_4\) is named Potassium Arsenate.

Step 5: Ag2TeO4 - Tellurium's Group and Compound Name

Tellurium (\(\mathrm{Te}\)) shares the same group as sulfur and selenium (Group 16). Since \(\mathrm{TeO}_4^{2-}\) can be likened to \(\mathrm{\ SO}_4^{2-}\) which forms sulfate, \(\mathrm{TeO}_4^{2-}\) forms tellurate. Thus, \(\mathrm{Ag}_2\mathrm{TeO}_4\) is named Silver Tellurate.

Key Concepts

Periodic Table Groups

The periodic table is an essential tool in chemistry, organized in a way that groups elements with similar properties together. These groups, or columns, are numbered from 1 to 18. By understanding these groupings, you can predict the behavior of elements in chemical reactions. Elements within the same group tend to have similar valence electron configurations, which leads to analogous chemical behavior.

For instance, elements in Group 16, like oxygen, sulfur, selenium, and tellurium, often form compounds with similar structures. Understanding these similarities can help in predicting the formation and naming of compounds.

Compound Formation

Compounds form when elements chemically bond together in fixed proportions. Typically, they combine to achieve a stable electron configuration, often resembling that of the nearest noble gas.

Understanding compound formation involves identifying the valency and typical bonding patterns of elements involved. For example, magnesium oxide (\(\mathrm{MgO}\)) forms when magnesium (Group 2) bonds with oxygen (Group 16). This pattern can be extended to predict that magnesium will similarly bond with sulfur, forming magnesium sulfide (\(\mathrm{MgS}\)). These predictions rely heavily on recognizing the positions of elements in the periodic table and understanding their typical bonding methods.

Element Analogies

An analogy in chemistry allows us to draw parallels between known and unknown situations. By understanding how one element behaves, we can predict the behavior of another element within the same group. For example, knowing that sulfur forms sulfates, we can infer that selenium (also in Group 16) will form selenates.

This method is particularly useful when learning about less common elements by comparing them with elements that share the same periodic table group. It simplifies the process of compound naming and formation prediction by leveraging known chemical behaviors.

Systematic Naming

Systematic naming in chemistry is a logical way of naming compounds based on their elemental makeup and structure. This process, often guided by IUPAC rules, allows chemists to communicate clearly about chemical substances.

For instance, the name Sodium Selenite for \(\mathrm{Na}_2\mathrm{SeO}_3\) is derived from selenium’s position in the periodic table and its analogy with sulfur. In this name, 'Selenite' indicates the selenium-based analog of sulfite. By learning the systematic approach, students can accurately name and interpret the composition of various chemical compounds, like Aluminum Antimonate for \(\mathrm{AlSbO}_4\), Potassium Arsenate for \(\mathrm{K}_3\mathrm{AsO}_4\), and Silver Tellurate for \(\mathrm{Ag}_2\mathrm{TeO}_4\).

Overall, systematic naming emphasizes order and predictability in the language of chemistry.