[Free Registration/Login may be required to access all resource tools.] In the following online tutorial students will be able to determine the number of valence electrons for any element and draw an electron dot diagram for any atom. They will use the octet rule to predict the charges of the most common ions formed by the representative elements and write electron configurations for ions. Students will also identify other atoms or ions that are isoelectronic with a particular ion. Know that transition metal ions with either half-filled or completely filled d sublevels are particularly stable.