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💏intro to chemistry review

Se2-

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Se2- is the diatomic selenide ion, which consists of two selenium atoms bonded together and carrying a 2- charge. This ion is an important species in the context of ionic bonding, as it can form ionic compounds with various cations.

5 Must Know Facts For Your Next Test

  1. The Se2- ion has a stable electronic configuration with a full valence shell, contributing to its tendency to form ionic bonds.
  2. Compounds containing the Se2- ion, such as sodium selenide (Na2Se) and calcium selenide (CaSe), are important in various industrial and technological applications.
  3. The Se2- ion can substitute for the sulfide ion (S2-) in some ionic compounds, leading to the formation of selenides.
  4. The size and electronegativity of the selenium atom compared to the sulfur atom can affect the properties of the resulting selenide compounds.
  5. Selenides can exhibit unique optical, electronic, and catalytic properties, making them valuable in fields like optoelectronics, energy storage, and catalysis.

Review Questions

  • Explain the formation of the Se2- ion and its role in ionic bonding.
    • The Se2- ion is formed when a selenium atom gains two electrons to achieve a stable octet electronic configuration. This results in the selenium atom carrying a 2- charge, which allows it to participate in ionic bonding with positive cations, such as sodium (Na+) or calcium (Ca2+). The formation of ionic compounds between Se2- and these cations is driven by the electrostatic attraction between the oppositely charged ions, leading to the creation of stable, crystalline structures.
  • Discuss the factors that influence the properties of selenide compounds compared to sulfide compounds.
    • The properties of selenide compounds can differ from those of their sulfur-containing counterparts due to the larger atomic size and lower electronegativity of selenium compared to sulfur. These differences can affect the strength and polarity of the ionic bonds, as well as the overall crystal structure and packing of the ions. Additionally, the unique electronic configuration of selenium can contribute to the optical, electronic, and catalytic properties of selenide materials, making them useful in various technological applications.
  • Evaluate the importance of the Se2- ion in the context of ionic bonding and its potential applications.
    • The Se2- ion is a crucial species in the study of ionic bonding, as it demonstrates the ability of selenium to form stable, negatively charged ions that can participate in the formation of ionic compounds. These selenide compounds have found important applications in fields such as optoelectronics, energy storage, and catalysis, where their unique properties can be leveraged. The understanding of the Se2- ion and its role in ionic bonding is essential for comprehending the behavior and potential uses of selenium-based materials in various technological and industrial contexts.