Sodium chloride

Definition

Sodium chloride, commonly known as table salt, is an ionic compound composed of sodium (Na\(^+\)) and chloride (Cl\(^-\)) ions. It is a classic example of a crystal structure formed through ionic bonding, showcasing the arrangement of ions in a three-dimensional lattice that is characteristic of many common crystal structures.

5 Must Know Facts For Your Next Test

1. Sodium chloride crystallizes in a face-centered cubic (FCC) lattice structure, where each sodium ion is surrounded by six chloride ions and vice versa.
2. The melting point of sodium chloride is 801 °C, which reflects the strength of the ionic bonds holding the lattice together.
3. In addition to being widely used as a seasoning, sodium chloride plays critical roles in biological systems, including nerve transmission and fluid balance.
4. When dissolved in water, sodium chloride dissociates into its constituent ions, Na\(^+\) and Cl\(^-\), making it an essential electrolyte in various chemical and biological processes.
5. Sodium chloride is highly soluble in water due to the strong attraction between water molecules and the individual ions.

Review Questions

• How does the ionic bonding in sodium chloride contribute to its crystal structure?
  • Ionic bonding in sodium chloride involves the transfer of electrons from sodium atoms to chlorine atoms, resulting in positively charged sodium ions and negatively charged chloride ions. These oppositely charged ions attract each other and arrange themselves into a highly ordered three-dimensional lattice structure. This arrangement minimizes the energy of the system and stabilizes the compound, showcasing the fundamental principles of ionic bonding and its impact on crystal formation.
• Compare the crystal structure of sodium chloride with that of another common ionic compound like cesium chloride. What are the key differences?
  • Both sodium chloride and cesium chloride are ionic compounds with distinct crystal structures. Sodium chloride adopts a face-centered cubic lattice, while cesium chloride has a body-centered cubic structure. In sodium chloride, each ion has six neighbors, while in cesium chloride, each cesium ion is surrounded by eight chloride ions. This difference in coordination number influences their physical properties, including melting points and solubility.
• Evaluate the significance of sodium chloride's solubility in water regarding its applications in biological systems and industry.
  • The solubility of sodium chloride in water is crucial for its role as an electrolyte in biological systems, where it helps regulate nerve impulses and maintain fluid balance. In industrial applications, this property allows for efficient transport of salt solutions used in processes like de-icing roads or producing chlorine gas through electrolysis. The ability to dissociate into Na\(^+\) and Cl\(^-\) ions when dissolved makes it essential for various chemical reactions and contributes to its versatility across different fields.

Related terms

Ionic Bonding: A type of chemical bond that occurs between two ions of opposite charges, where electrons are transferred from one atom to another.

Crystal Lattice:

A three-dimensional arrangement of atoms or ions in a crystalline solid, defining the structure and symmetry of the crystal.

Cubic Structure: A type of crystal system where the unit cell has a cube shape, common in materials like sodium chloride.