A portion of a two-dimensional 'slab' of NaCl(s) is shown here (see Figure 8.2) in which the ions are numbered. (d) Consider ion 5. How many repulsive interactions are shown for it?

Key Concepts

Ionic Bonding

Ionic bonding occurs when atoms transfer electrons, resulting in the formation of charged ions. In NaCl, sodium (Na) loses an electron to become Na+, while chlorine (Cl) gains an electron to become Cl-. The electrostatic attraction between these oppositely charged ions forms a strong ionic bond, creating a crystalline lattice structure characteristic of ionic compounds.

Repulsive Interactions

Repulsive interactions in ionic compounds arise when like-charged ions are brought close together. These interactions occur due to the electrostatic forces that push ions apart, which is crucial for maintaining the stability of the crystal lattice. In the context of NaCl, each ion experiences repulsion from other ions of the same charge, affecting the overall structure and stability of the solid.

Coordination Number

The coordination number refers to the number of nearest neighbor ions surrounding a given ion in a crystal lattice. In NaCl, each Na+ ion is surrounded by six Cl- ions and vice versa, leading to a coordination number of 6. Understanding the coordination number helps in analyzing the spatial arrangement of ions and the resulting interactions, including both attractive and repulsive forces.