Most substances are found combined in nature. They are more ______________________ this way than the elements were while uncombined because they now have full outer shells. Chemical bonds form in order to increase stability. The ______________________ ______________________ (group 8 or group 0 elements) are an exception to this. They are found in nature uncombined. Their atoms already have full shells and are stable the way they are.

The rest of the elements in the Periodic Table will react to fill their outer shells by:

1. ______________________ electrons from the outer shell (forming cations)

2. ______________________ electrons to the outer shell (forming anions)

3. ______________________ electrons in the outer shell