key term - I2

Definition

I2, or diatomic iodine, is a chemical compound that is a member of the halogen group of elements. It is a solid at room temperature and has a characteristic purple-black color and distinctive odor. I2 is an important element in the context of the topics covered in section 18.11 Occurrence, Preparation, and Properties of Halogens.

5 Must Know Facts For Your Next Test

1. Iodine is the heaviest of the stable halogens and is the only halogen that is a solid at room temperature.
2. I2 is commonly found in the earth's crust, primarily in the form of iodide salts, and is also present in seawater.
3. I2 can be prepared by the reaction of iodide salts with oxidizing agents, such as chlorine or hydrogen peroxide.
4. I2 is a strong oxidizing agent and can participate in a variety of chemical reactions, including substitution, addition, and redox reactions.
5. I2 is used in various applications, including disinfectants, photographic materials, and as a nutritional supplement for iodine deficiency.

Review Questions

• Explain the occurrence and preparation of I2 in the context of the halogens.
  • I2 is found naturally in the earth's crust, primarily in the form of iodide salts, and is also present in seawater. It can be prepared by the reaction of iodide salts with oxidizing agents, such as chlorine or hydrogen peroxide. This preparation method is important in the context of the halogens, as it demonstrates the reactivity of the halogen group and the ability to extract and produce individual halogen elements like iodine.
• Describe the physical and chemical properties of I2 that are relevant to the study of halogens.
  • I2 is a solid at room temperature with a characteristic purple-black color and distinctive odor. As a member of the halogen group, I2 is a strong oxidizing agent and can participate in a variety of chemical reactions, including substitution, addition, and redox reactions. These properties are important in understanding the general reactivity and behavior of the halogens, as well as their potential applications and uses.
• Analyze the role of I2 in the context of the broader properties and trends observed in the halogen group.
  • I2 is the heaviest of the stable halogens, and its reactivity is the lowest among the halogens, decreasing from fluorine to iodine. This trend in reactivity is a key characteristic of the halogen group and is influenced by factors such as atomic size and electronegativity. Understanding the position of I2 within this reactivity trend, as well as its specific physical and chemical properties, is crucial for predicting and explaining the behavior of halogens in various chemical processes and applications.

Related terms

Halogens:

The halogen group consists of five elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). These elements are highly reactive nonmetals that form compounds with most other elements.

Diatomic Molecules:

Diatomic molecules are chemical compounds composed of two atoms of the same element, such as I2, H2, and N2. These molecules are common among the halogens and other nonmetal elements.

Reactivity of Halogens: The halogens are highly reactive elements due to their tendency to gain or share electrons in chemical reactions. The reactivity of halogens decreases from fluorine to iodine, with fluorine being the most reactive and iodine being the least reactive.