1. The Periodicities of the Periodic Table

2. Ionization energy
energy needed to make an ion by losing electrons

3. First Ionization Energy
Definition:
energy needed to remove the most loosely held e-
Valence electron
high E electron
Outermost electron

4. 1st

5. Why 1st? Is there a 2nd? 2nd ionization energy 3rd ionization energy
Energy needed to remove the second electron
3rd ionization energy
Energy needed to remove the third electron

6. 1st
3rd e- removed
2nd e- removed

8. What’s holding the e- in place?
PROTONS
“Opposites attract”
There is a force of attraction between protons (+) and electrons (-)

9. Ionization E trend? 3 p+ 9 p+
As move across a period…IE increases. WHY?
3 p+
9 p+

10. As you go across a period
a proton and an electron are being added
more p+ hold the e- tighter when in the same energy level
Increasing nuclear charge

11. More E to remove As move UP a group … IE increases. WHY? Period 1
Let’s figure it out . . .
More E to remove

12. Potassium
19 p+

13. Sodium
11 p+

14. Lithium
3 p+

15. because . . . As you go up a group
INCREASES
because . . .
As you go up a group
the electron shells get closer to the nucleus and can hold on to the e- tighter.
ALSO………………….

16. Potassium
19 p+

17. SHIELDING as you go DOWN a group
Not only does the distance increase between the p+ and valence e-
e- in outer shells repel each other & makes them easier to remove

18. Who has the highest IEs?
Lowest?

19. Electronegativity
E-neg

20. Electronegativity
Ability of an atom to attract electrons of other atoms.
In other words. . .
Atoms with high e-neg are bullies that steal electrons

22. F Electronegativity INCREASES EXCEPT for Noble gases. WHY?
Periodic trend F
INCREASES
EXCEPT for Noble gases. WHY?
Already have full valence shell!

23. Summary
Atoms with
high electronegativities
also have
high ionization E

24. Atomic Radius
Radius
distance from the center of a circle (Nucleus) to the outermost edge (valence shell) R

25. Atomic Radius Periodicity
DECREASES
DECREASES

26. Why????? Why does atomic radius DECREASE as you move up a group?
Losing full Energy levels
Why does atomic radius DECREASE as you move across a period?
Increasing the # of p+ holds the e- in tighter

27. NOW Compare the radii of Na0 and Na+ POSITIVE Ionic radius is smaller
the radii of Cl0 and Cl-
NEGATIVE Ionic radius is larger

28. Compare 2 different elements
Compare the ionic radius of Mg2+ and the atomic radius of Ne.
The ionic radius of Mg2+ is smaller than the atomic radius of Ne
because the Mg 2+ ion has more p+ (12) than the Ne atom (10).

29. General Formulas of compounds
You can look at the groups on the periodic table and determine how they will combine with elements of different groups.

30. Group 1 Group 2 Group16 Group 17
1:1
General Formula: AB

31. Group 1 Group 2 Group16 Group 17
1:1
General Formula: AB

32. Group 1 Group 2 Group16 Group 17
2:1
General Formula: A2B

33. Group 1 Group 2 Group16 Group 17
1:2
General Formula: AB2

34. THE END