Question

Name each polyatomic ion. (a) \(\mathrm{IO}^{-}\) (b) \(\mathrm{IO}_{2}^{-}\) (c) \(\mathrm{IO}_{3}^{-}\) (d) \(\mathrm{IO}_{4}^{-}\)

Short answer

(a) Hypoiodite (b) Iodite (c) Iodate (d) Periodate

Step-by-step solution

Identify the Polyatomic Ions

First, recognize that each of the given species is a polyatomic ion, which is a charged species (ion) composed of two or more atoms covalently bonded.

Use Known Naming Conventions

Polyatomic ions with iodine and varying numbers of oxygen have specific names based on the number of oxygen atoms. The suffixes '-ite' and '-ate' are commonly used in the names of polyatomic ions, with '-ite' indicating one less oxygen atom than the '-ate' ion.

Name the Polyatomic Ions

For these ions, prefix 'hypo-' is used for the least number of oxygen atoms and prefix 'per-' is used for the most. Suffix 'ite' or 'ate' is added as follows: (a) With one oxygen atom, it's called hypoiodite. (b) With two oxygen atoms, it's called iodite. (c) With three oxygen atoms, it's iodate. (d) With four oxygen atoms, it's periodate.

Key concepts

Chemical Nomenclature

Understanding the language of chemistry starts with mastering chemical nomenclature, the system used to name chemical compounds. The goal of this system is to ensure that each chemical compound has a unique and universally accepted name. In the context of polyatomic ions, the nomenclature becomes even more specific.

For example, consider the ions with iodine and oxygen from the exercise. The naming conventions relate directly to the number of oxygen atoms in the ion. A specific set of prefixes and suffixes help identify these variations. The prefix 'hypo-' is used when an ion has the least number of oxygen atoms for that series, while 'per-' is used for the ion with the most oxygen. Suffixes '-ite' and '-ate' are added to signify a lesser or greater number of oxygen atoms, respectively. This precise language allows chemists to communicate complex chemical structures in a simple format, which is critical for sharing information and advancing the field of chemistry.

Inorganic Chemistry

Inorganic chemistry focuses on compounds that are not based on carbon-hydrogen bonds. This broad field covers a variety of substances, including metals, minerals, and, as seen in our exercise, polyatomic ions—groups of atoms bonded together that carry a charge. Unlike organic compounds, inorganic chemistry deals with ions and elements in various oxidation states, and these species often require specific naming rules.

It's important to familiarize oneself with the periodic table and understand how elements form compounds and interact with each other. In the case of polyatomic ions, it is essential to know how variations in the number of oxygen atoms affect the chemical properties and the names of the ions. Such knowledge is fundamental in synthesizing new compounds and predicting the outcome of chemical reactions.

Covalent Compounds

Covalent compounds are formed when two or more atoms share electrons in a bond. This type of bonding is contrasted with ionic bonding, in which electrons are transferred from one atom to another, creating charged particles, or ions. Polyatomic ions are a unique subset of covalent compounds where the atoms are covalently bonded, but the overall structure carries a net charge.

In our exercise, each ion features a combination of iodine and oxygen atoms, which are bound together through covalent bonds. However, the additional presence of charge is what classifies them as ions. This dual nature is an exciting area in chemistry because it combines aspects of both ionic and covalent compounds, influencing properties such as solubility, reactivity, and the ability to conduct electricity. The understanding of covalent bonding and resultant structures is a cornerstone of chemistry, which allows us to predict how molecules will interact and react.