Question

Selenium, an element required nutritionally in trace quantities, forms compounds analogous to sulfur. Name the following ions: (a) \(\mathrm{SeO}_{4}^{2-},(\mathbf{b}) \mathrm{Se}^{2-}\) (c) \(\mathrm{HSe}^{-}\), (d) \(\mathrm{HSeO}_{3}^{-}\).

Short answer

The ions are named as follows: (a) SeO4^2- is selenate, (b) Se^2- is selenide, (c) HSe^- is hydrogen selenide, and (d) HSeO3^- is hydrogen selenite.

Step-by-step solution

Ion (a): SeO4^2-

Using the analogy with sulfur, we observe that the equivalent sulfur ion is SO4^2-, which is named sulfate. Therefore, the name of the SeO4^2- ion is selenate.

Ion (b): Se^2-

Based on the analogy with sulfur, we see that the equivalent sulfur ion is S^2-, which is named sulfide. Consequently, the name of the Se^2- ion is selenide.

Ion (c): HSe^-

For this ion, the sulfur counterpart is HS^-, which is named hydrogen sulfide. As a result, the name of the HSe^- ion is hydrogen selenide.

Ion (d): HSeO3^-

The analogous sulfur ion for this compound is HSO3^-, which we know as hydrogen sulfite. Therefore, the name of the HSeO3^- ion is hydrogen selenite.

Key concepts

Selenium Compounds

Selenium is a fascinating element that shares many similarities with sulfur, primarily due to their position in the same group on the periodic table. This similarity allows selenium to form compounds that mirror those of sulfur. These compounds find numerous applications in both biology and industry. Selenium is often integral to the functioning of enzymes and is crucial for maintaining proper health in trace amounts.

Given its role and relative scarcity, understanding selenium compounds is important in fields like nutrition and pharmacology. Compounds such as selenate (SeO4^{2-}), are vital because they can participate in redox reactions, much like their sulfur counterpart, sulfate (SO4^{2-}). This ability makes them useful in various biochemical processes. Another common selenium compound is selenide (Se^{2-}), akin to sulfide (S^{2-}), which also highlights its chemical versatility.

Learning about these compounds not only enriches the study of selenium but also offers insight into the broader topic of periodic table trends and chemical analogies.

Ion Naming

Naming ions, especially for elements like selenium, requires an understanding of their similarity to other elements such as sulfur. This understanding helps us predict and systematically name selenium ions by observing their sulfur equivalents.

For instance, the ion (SeO4^{2-} corresponds to (SO4^{2-} , which is known as sulfate; thus, (SeO4^{2-} is named selenate. Similarly, (Se^{2-} parallels (S^{2-} , known as sulfide, leading us to name selenium's version selenide.

For more complex ions like (HSeO3^{-} , understanding the naming convention—hydrogen followed by sulfur or selenium—helps us systematically arrive at hydrogen selenite, much like hydrogen sulfite for (HSO3^{-} . By following these analogies, we can confidently name a variety of selenium ions.

Sulfur Analog Compounds

Sulfur and selenium belong to the chalcogen family, known for a wealth of chemical analogs. These analogs are particularly evident in the types of compounds these elements form. Sulfur analog compounds involve substituting sulfur in various chemical formulas with selenium to recognize patterns in reactivity and properties.

Consider the compounds selenate (SeO4^{2-} and selenide (Se^{2-} ; they serve as direct counterparts to sulfate (SO4^{2-} and sulfide (S^{2-} , respectively. These analogs not only assist in naming but also in understanding chemical behaviors.

Sulfur analogs have practical implications. For instance, hydrogen selenide (HSe^{-} and hydrogen selenite (HSeO3^{-} reflect their sulfur counterparts' properties, such as hydrogen sulfide (HS^{-} and hydrogen sulfite (HSO3^{-} . Applying this knowledge can provide insight into designing similar compounds with desired properties for industrial and pharmaceutical uses.