8.2. Ionic Bonds and Ionic Compounds http://www.ck12.org
8.2 Ionic Bonds and Ionic Compounds
Lesson Objectives
- Describe the general properties that distinguish ionic compounds from other substances.
- Define and give examples of ionic compounds. Be able to predict which elements are likely to form ionic
compounds with each other. - Describe the crystal lattice structures adopted by ionic compounds.
- Define lattice energy and explain what it measures.
Lesson Vocabulary
- ionic bond: The resulting attraction between the positively charged cations and negatively charged anions
- crystal lattice: A three-dimensional sturcture formed by ions in order to maximize the number of attractive
interactions while minimizing the repulsive ones. - lattice energy: The amount of energy needed to completely pull apart an ionic substance into isolated ions.
- dissolution: Occurs when water interacts with the ions in the crystal lattice, causing the lattice to break apart.
Check Your Understanding
- Give some examples of commonly encountered ions.
- Draw electron dot diagrams for atoms of the following elements:
a. calcium
b. oxygenIntroduction
In the last section, we saw that elements may lose or gain electrons to become isoelectronic with the nearest noble
gas. Where do the electrons go when an element loses them to become a cation? Where do electrons come from
when an element gains them to become an anion? For an atom to gain or lose electrons, there must be an interaction
between two different chemical species. If electrons are fully exchanged, then we consider this interaction to be
ionic. The resulting attractions between the positively charged cations and the negatively charged anions are referred
to asionic bonds.