1. Octet Rule
& Ions
Unit 1 Notes

2. Valence Shell

3. All atoms want 8 electrons in their valence shell.
This is known as the octet rule.
Atoms will GAIN or LOSE electrons to get 8 electrons in their valence shell.
When an atom gains or loses electrons it becomes an ion.

4. Gaining electrons forms an anion. (negatively charged)
Atoms will GAIN or LOSE electrons to get 8 electrons in their valence shell.
When an atom gains or loses electrons it becomes an ion.
Gaining electrons forms an anion. (negatively charged)
Losing electrons forms a cation. (positively charged)

5. Gaining electrons forms an anion. (negatively charged)
Atoms will GAIN or LOSE electrons to get 8 electrons in their valence shell.
When an atom gains or loses electrons it becomes an ion.
Gaining electrons forms an anion. (negatively charged)
Losing electrons forms a cation. (positively charged)

6. Atoms will GAIN or LOSE electrons to get 8 electrons in their valence shell.
Draw the Bohr model for sodium. How many electrons are in its valence shell?
Would it be easier for sodium to lose or gain electrons to get a new valence shell with eight electrons?

7. Atoms will GAIN or LOSE electrons to get 8 electrons in their valence shell.