Question

Give the name of each of the following polyatomic ions. a. ${\mathrm{NH}}_4^{+}$ b. ${\mathrm{H}}_2{\mathrm{PO}}_4^{-}$ c. ${\mathrm{SO}}_4^{2-}$ d. ${\mathrm{HSO}}_3^{-}$ e. ${\mathrm{ClO}}_4^{-}$ f. ${\mathrm{IO}}_3^{-}$

Short answer

a. Ammonium b. Dihydrogen phosphate c. Sulfate d. Hydrogen sulfite e. Perchlorate f. Iodate

Step-by-step solution

Identify the ion a: ${\mathrm{NH}}_4^{+}$

For the ion ${\mathrm{NH}}_4^{+}$, we recognize it as a common polyatomic ion. The ion contains one nitrogen atom and four hydrogen atoms, and it has a charge of +1.

Give the name of ion a

The name of the ion ${\mathrm{NH}}_4^{+}$ is Ammonium.

Identify the ion b: ${\mathrm{H}}_2{\mathrm{PO}}_4^{-}$

For the ion ${\mathrm{H}}_2{\mathrm{PO}}_4^{-}$, we can recognize it as a less common polyatomic ion. The ion consists of two hydrogen atoms, one phosphorus atom, four oxygen atoms, and has a charge of -1.

Give the name of ion b

The name of the ion ${\mathrm{H}}_2{\mathrm{PO}}_4^{-}$ is Dihydrogen phosphate.

Identify the ion c: ${\mathrm{SO}}_4^{2-}$

For the ion ${\mathrm{SO}}_4^{2-}$, we recognize it as a common polyatomic ion. The ion contains one sulfur atom and four oxygen atoms, and it has a charge of -2.

Give the name of ion c

The name of the ion ${\mathrm{SO}}_4^{2-}$ is Sulfate.

Identify the ion d: ${\mathrm{HSO}}_3^{-}$

For the ion ${\mathrm{HSO}}_3^{-}$, we can recognize it as a less common polyatomic ion. The ion consists of one hydrogen atom, one sulfur atom, three oxygen atoms, and has a charge of -1.

Give the name of ion d

The name of the ion ${\mathrm{HSO}}_3^{-}$ is Hydrogen sulfite.

Identify the ion e: ${\mathrm{ClO}}_4^{-}$

For the ion ${\mathrm{ClO}}_4^{-}$, we can recognize it as a less common polyatomic ion. The ion consists of one chlorine atom, four oxygen atoms, and has a charge of -1.

Give the name of ion e

The name of the ion ${\mathrm{ClO}}_4^{-}$ is Perchlorate.

Identify the ion f: ${\mathrm{IO}}_3^{-}$

For the ion ${\mathrm{IO}}_3^{-}$, we can recognize it as a less common polyatomic ion. The ion consists of one iodine atom, three oxygen atoms, and has a charge of -1.

Give the name of ion f

The name of the ion ${\mathrm{IO}}_3^{-}$ is Iodate.

Key concepts

Chemical Nomenclature

Chemical nomenclature is a systematic method for naming chemical compounds and ions. It's essential for clear communication in the field of chemistry, ensuring that each compound has a unique and universally understood name. The rules for naming polyatomic ions, which are ions composed of two or more atoms covalently bonded together, involve identifying the elements present, their oxidation numbers, and the overall charge of the ion.

• If an ion contains oxygen, the names might include a prefix or suffix to indicate the number of oxygen atoms present, such as 'per-' for an extra oxygen (compared to the -ate ion), or 'hypo-' for one fewer oxygen (compared to the -ite ion).
• The suffix '-ate' is used for the most common or representative polyatomic ion of an element with oxygen, while '-ite' is used for an ion with fewer oxygen atoms.
• When hydrogen or dihydrogen is added to an anionic polyatomic ion, 'hydrogen' or 'dihydrogen' is placed before the name of the ion.
• For positively charged polyatomic ions, known as cations, common names are often used, such as ammonium for $N{H}_4^{+}$.

Understanding these rules and patterns can help students decipher the names of complex ions and communicate effectively about these substances in chemistry.

Ammonium Ion

The ammonium ion, depicted as $N{H}_4^{+}$, is one of the most fundamental polyatomic ions in chemistry. It consists of one nitrogen atom surrounded by four hydrogen atoms and carries a positive charge. The ammonium ion is unique because it resembles an alkali metal ion in its properties, including its ability to conduct electricity in liquid form and its occurrence in a wide variety of salts.

The naming convention for this ion is quite straightforward; since it is a common polyatomic ion and carries a positive charge, it's given the name 'ammonium.' This ion plays a critical role in various biological and environmental processes and is also found in many fertilizers due to its nitrogen content, which plants require for growth.

Phosphate Ions

Phosphate ions include several related ions with a phosphorus atom and oxygen atoms bound together. The most common phosphate ion is $P{O}_4^{3-}$ with a -3 charge referred to as 'phosphate.' However, when hydrogen ions are added to the basic phosphate ion, it forms different polyatomic ions, such as $HP{O}_4^{2-}$, called 'hydrogen phosphate', and $H_{2}P{O}_4^{-}$, named 'dihydrogen phosphate'.

Each variation indicates a protonation level of the phosphate ion, with dihydrogen phosphate having two accessible protons. It’s important to recognize these differences because they can significantly affect the ion's chemical reactivity and how it interacts in biological systems, such as in ATP, the energy currency of cells, or in fertilizers.

Sulfate Ion

The sulfate ion, symbolized as $S{O}_4^{2-}$, is a negatively charged polyatomic ion. It is characterized by a central sulfur atom bonded to four oxygen atoms in a tetrahedral arrangement. The sulfate ion is utilized widely in chemical compounds, notably in industrial chemicals, detergents, and as a desiccant.

Students may also encounter variants of the sulfate ion, such as the bisulfate or hydrogen sulfate ion $HS{O}_4^{-}$, which contains one less oxygen atom and is named by adding the 'hydrogen' prefix due to the presence of an additional hydrogen. Recognizing the patterns of sulfate and its variations can help students understand their prevalence in not only chemistry but also in environmental processes, as sulfates are often present in natural waters.