1. How Elements Form Compounds Some atoms lose or gain electrons to become stable charged particles called ions When atoms loses electrons, they form positively charged ions called cations When atoms gain electrons, they form negatively charged ions called anions.

2. Sodium chloride is a relatively harmless compound because the sodium and chlorine atoms have stable ions. The compound formed is called an ionic compound because it is made up of positive and negative ions that have resulted from the transfer an electronv of from a metal to a nonmetal. The positive and negative ions are attracted to each other because they have opposite charges.

4. When ionic compounds are placed in water, the ions separate and are surrounded by water molecules. They are electrolytes. They are also conductive

5. Ionic Charges and Chemical Families Review structure of the atom How some atoms can form stable ions by gaining or losing electrons You have also learned that the PT is a useful organizing tool for predicting behaviour of substances

6. The location of the alkalis metals (dark green), the alkaline earth metals (light green), and the halogens (red) in the PT Activity