Question

Two different halogens are present in a series known as interhalogen compounds. Name these interhalogen compounds: (a) IBr; (b) \(\mathrm{BrF}_{3} ;\) (c) \(\mathrm{I}_{2} \mathrm{Cl}_{6} ;\) (d) \(\mathrm{ClF}_{5}\); (e) IF \(_{7}\).

Short answer

(a) Iodine monobromide, (b) Bromine trifluoride, (c) Iodine hexachloride, (d) Chlorine pentafluoride, (e) Iodine heptafluoride.

Step-by-step solution

Identifying the Principal Halogen

For each interhalogen compound, determine which halogen has the higher atomic number, as this will be named first in the compound.

Naming of IBr

The compound IBr consists of iodine (I) and bromine (Br). Iodine has a higher atomic number (53) than bromine (35), so iodine is named first. Therefore, the name of the compound is Iodine monobromide.

Naming of BrF3

The compound BrF3 consists of bromine (Br) and fluorine (F). Fluorine has a lower atomic number (9) than bromine (35), so bromine is named first. The name of the compound is Bromine trifluoride.

Naming of I2Cl6

The compound I2Cl6 consists of iodine (I) and chlorine (Cl). Iodine has a higher atomic number (53) than chlorine (17), so iodine is named first. The name of the compound is Iodine hexachloride.

Naming of ClF5

The compound ClF5 consists of chlorine (Cl) and fluorine (F). Fluorine has a lower atomic number (9) than chlorine (17), so chlorine is named first. The name of the compound is Chlorine pentafluoride.

Naming of IF7

The compound IF7 consists of iodine (I) and fluorine (F). Although fluorine is known for its high electronegativity, iodine has a higher atomic number (53) than fluorine (9), so iodine is named first. The name of the compound is Iodine heptafluoride.

Key concepts

Atomic Number

In chemistry, the atomic number is a crucial concept used to identify elements on the periodic table. It represents the number of protons found in the nucleus of an atom. This number is unique to each element and determines the element's place in the periodic table as well as its chemical properties.
In the context of interhalogen compounds, understanding atomic numbers is essential. Interhalogen compounds are combinations of different halogens. To correctly name them, we first determine the primary halogen based on atomic numbers. The halogen with the higher atomic number is generally named first in the compound's chemical nomenclature. For example, in the compound IBr, iodine is listed first because its atomic number, 53, is greater than bromine's, which is 35.
This rule helps maintain a systematic approach to naming compounds, allowing easy communication and understanding among chemists.

Halogen Chemistry

Halogen chemistry involves elements from Group 17 of the periodic table which include fluorine, chlorine, bromine, iodine, and astatine. These elements are highly reactive due to their seven valence electrons, which makes them eager to gain an electron to achieve a stable octet configuration.
Interhalogen compounds are a fascinating study area within halogen chemistry. They are formed by combining two different halogens. This unique combination results in a variety of compounds with distinctive chemical properties. For instance, fluorine, being highly reactive, forms compounds with almost all other halogens, despite having the lowest atomic number in its group.
Halogen chemistry is significant because of its applications in industrial processes, medicine, and environmental science. Understanding the reactivity and properties of these elements is essential for advancements in material science and catalysis.

Chemical Nomenclature

Chemical nomenclature is the system used to name chemical compounds in a structured and standardized format. This system is vital for scientists around the world to communicate clearly without confusion.
In interhalogen compounds, nomenclature follows specific rules to ensure consistency. The primary rule is to position the halogen with the higher atomic number first in both the written formula and the compound name. For example:

• IBr is named Iodine monobromide because iodine's atomic number (53) is higher than bromine's (35).
• BrF₃ is called Bromine trifluoride, with bromine (atomic number 35) preceding fluorine (atomic number 9).

Furthermore, prefixes such as mono-, di-, tri-, tetra-, etc., are used to indicate the number of atoms in molecules beyond binary compounds.
These naming conventions simplify the writing and identification of chemical formulas, facilitating a shared language across scientific disciplines.