1. The Stable Octet & Ion Formation

2. Atoms (elements) are MOST STABLE when they have a FULL OUTER SHELL. For many elements, they are stable when the outer shell holds eight electrons. This electron arrangement is called a STABLE OCTET. Some ELEMENTS have a full outer electron shell (VALENCE SHELL), for example, helium, neon and argon. Because these elements do not want to lose or gain electrons, they are STABLE -­‐ they do not react.

3. However, for the REST OF THE PERIODIC TABLE, the ATOMS have an PARTIALLY FILLED VALENCE electron arrangement. These atoms will tend toGAIN OR LOSE VALENCE ELECTRONS to achieve a Stable Octet and BECOME IONS. An ION is a CHARGED ATOM, in which the ELECTRONS AND PROTONS ARE NOT THE SAME. When an atom LOSES valence electron(s), it will form a POSTIVE ion. When an atom GAINS valence electron(s), it will form a NEGATIVE ion.

4. MetalsWhen an atom has 1, 2 or 3 electrons in its outer shell (VALENCE SHELL), it will tend to lose these electrons to achieve a stable octet electron arrangement.

5. Non-­‐metalsWhen an atom has 5, 6 or 7 electrons in its outer shell (VALENCE SHELL), it will tend to gain electrons to achieve a stable octet electron arrangement.

6. WRITING IONS Write the following atoms in their correct ION form. Li N S Al F Mg