8.1. Ions http://www.ck12.org
8.1 Ions
Lesson Objectives
- Be able to determine the number of valence electrons for any element and draw an electron dot diagram for
any atom. - Use the octet rule to predict the charges of the most common ions formed by the representative elements.
- Write electron configurations for ions.
- Identify other atoms or ions that are isoelectronic with a particular ion.
- Know that transition metal ions with either half-filled or completely filleddsublevels are particularly stable.
Lesson Vocabulary
- electron dot diagram
- isoelectronic
- octet rule
Check Your Understanding
Recalling Prior Knowledge
- What is the Aufbau principle?
- What is the name of the energy required to remove an electron from a neutral atom?
- How does the energy required to remove the first electron from an atom compare to the energy necessary to
remove subsequent electrons?
As you learned in previous chapters, ions are formed when atoms lose or gain electrons. Metal atoms have relatively
few valence electrons, so when neutral metals undergo chemical reactions, they tend to lose those valence electrons.
Nonmetals have more valence electrons than metals, so when nonmetals undergo reactions with metals, they tend
to gain electrons. In this lesson, we take a closer look at ions and the physical and chemical properties of ionic
compounds.
Electron Dot Diagrams
Recall that the valence electrons of an atom are the electrons that reside in the highest occupied principal energy
level. Valence electrons are primarily responsible for the chemical properties of various elements. The number
of valence electrons can be easily determined from the electron configuration. Several examples from the second