1. IONS and E config Ions are atoms that have lost or gained electrons.
Remember that the number of protons cannot change for an element.
When an atom gains more electrons than the number of protons it has it will have a negative charge.

2. When an element loses more electrons than the number of protons it has, it will have a positive charge.
What drives atoms to give away electrons or take on more?

3. Driving Force Full Energy Levels are very low energy
Noble Gases have full orbitals
Atoms behave in ways to achieve noble gas configuration

4. Ionic Size Cations are positive ions Cations form by losing electrons
Cations are smaller than the atom they come from
Metals form cations
Cations of representative elements have noble gas configuration.

5. Ionic size Anions are negative ions Anions form by gaining electrons
Anions are bigger than the atom they come from
Nonmetals form anions
Anions of representative elements have noble gas configuration.

6. Configuration of Ions
Ions of representative elements have noble gas configuration
Na is 1s22s22p63s1
Forms a 1+ ion - 1s22s22p6
Same configuration as neon
Metals form ions with the configuration of the noble gas before them - they lose electrons

7. Configuration of Ions
Non-metals form ions by gaining electrons to achieve noble gas configuration.
They end up with the configuration of the noble gas after them.

8. Group trends H1+ Li1+ Na1+ K1+ Rb1+ Cs1+ Adding energy level
Ions get bigger as you go down
Li1+
Na1+
K1+
Rb1+
Cs1+

9. Periodic Trends N3- O2- F1- B3+ Li1+ C4+ Be2+
Across the period nuclear charge increases so they get smaller.
Energy level changes between anions and cations
N3-
O2-
F1-
B3+
Li1+
C4+
Be2+

10. Keeping Track of Electrons
The electrons responsible for the chemical properties of atoms are those in the outer energy level.
Valence electrons - The s and p electrons in the outer energy level.
Core electrons -those in the energy levels below.
Basis for shorthand

11. Keeping Track of Electrons
Atoms in the same column
Have the same properties because
Have the same outer electron configuration.
Have the same valence electrons.
Found by looking up the group number on the periodic table.
Group 2A - Be, Mg, Ca, etc.-
2 valence electrons

12. Lewis Dot diagrams help us determine the charge

13. X Electron Dot diagrams A way of keeping track of valence electrons.
How to write them
Write the symbol.
Put one dot for each valence electron
Don’t pair up until they have to X

14. The Electron Dot diagram for Nitrogen
Nitrogen has 5 valence electrons.
First we write the symbol. N
Then add 1 electron at a time to each side.
Until they are forced to pair up.

15. Write the electron dot diagram forNa Mg C O F Ne He

16. Electron Configurations for Cations
Metals lose electrons to attain noble gas configuration.
They make positive ions.
Na 1s22s22p63s1 - 1 valence electron
Na+ 1s22s22p6 -noble gas configuration

17. Electron Dots For Cations
Metals will have few valence electrons Ca

18. Electron Dots For Cations
Metals will have few valence electrons
These will come off Ca

19. Electron Dots For Cations
Metals will have few valence electrons
These will come off
Forming positive ions
Ca2+

20. Electron Configurations for Anions
Nonmetals gain electrons to attain noble gas configuration.
They make negative ions.
S 1s22s22p63s23p4 - 6 valence electrons
S2- 1s22s22p63s23p6 -noble gas configuration.

21. Electron Dots For Anions
Nonmetals will have many valence .electrons.
They will gain electrons to fill outer shell. P
P3-

22. Practice Use electron dot diagrams to show how the following form ionsAl Cl C

23. Stable Electron Configurations
All atoms react to achieve noble gas configuration.
Noble gases have 2 s and 6 p electrons.
8 valence electrons .
Also called the octet rule. Ar