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

cationsWhen atoms gain electrons, they form

negatively charged ions called anions.

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.

When ionic compounds are placed in water, the

ions separate and are surrounded by water

molecules. They are electrolytes.

They are also conductive

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

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

Activity