1. Write the Complete Electron Configuration for:
Warm Up
Write the Complete Electron Configuration for:
Lithium, Li
Sodium, Na
Rubidium, Rb

2. Electron Configuration and Periodic Properties
Periodic Trends
Electron Configuration and Periodic Properties

3. Periodic Trends
The Groups and Periods of the Periodic Table display predictable trends that include:
Atomic Radius
Ionization Energy
Electronegativity

4. Atomic Radius
Atomic Radius refers to the size of the atom; it is the distance from the center of the nucleus to the “edge” of the outermost energy level.

5. Atomic Radius
Atomic Radius increases to the LEFT and DOWN

6. Atomic Radius Increases DOWN (↓) a Group
Higher energy levels have larger orbitals
Shielding – core e- block the attraction between the nucleus and the valence e-
Decreases RIGHT (→) across a Period
Stronger Nuclear Charge (more p+) without additional shielding (shells) pulls e- in tighter.

9. Shielding
Shielding refers to the reduced attraction felt between the outer shell electrons and nucleus due to the ‘shielding’ effect of the inner shell electrons.
The nuclear charge felt by the outer shell electrons is much less compared to that of the inner shell electrons, and are therefore held less tightly held.

10. Nuclear Charge
As we move left to right across a period, more p+ and e- are added to the existing energy levels.
The nucleus is more positive (+) and the e- cloud is more negative.
The Nuclear Charge is the pull that the (-) e-“feels” from the (+) nucleus.
The increased attraction pulls the cloud in, making atoms smaller.

11. Atomic Radius Practice
Which of the following elements has the largest atomic radius: Li, O, C, or F? Which has the smallest radius?
Li, F

12. Atomic Radius Practice
Of the elements P, Mg, Ca, and Ba, which has the largest atomic radius? Which has the smallest?
Ba, P

13. Atomic Radius Practice
Arrange the following elements in order of increasing Atomic Radii.
Al, Ar, Cs, Na
Ar, Al, Na, Cs

14. Atomic Radius
Draw arrows like this on your handout and explain the Atomic Radii Trend in your own words:

15. Ionization Energy
Ionization Energy is the energy required to remove an electron from an atom.

16. Ionization Energy
Ionization Energy Increases UP and to the RIGHT

17. Ionization Energy
Ionization Energy is the opposite of Atomic Radius….As (A.R.) decreases, (I.E.) increases, and vice versa.
Why?
As atoms get smaller, the e- get closer to the (+) nucleus where there is a greater Nuclear Charge (attraction) between them.
As atoms get larger, the e- get farther from the nucleus, making them easier to remove.
More ‘Shielding’
Lower Nuclear Charge

18. Ionization Energy Practice
Which of the following elements has the largest Ionization Energy: O, C, Be, or Ne? Which has the smallest?
Ne, Be

19. Ionization Energy Practice
Of the elements Ca, Ba, Mg, and Ra, which has the largest Ionization Energy? Which has the smallest?
Mg, Ra

20. Ionization Energy Practice
Arrange the following elements in order of increasing Ionization Energy.
Mg, B, Cl, K
K, Mg, B, Cl

21. Ionization Energy (Potential)
Draw arrows like this on your handout and explain the Ionization Energy Trend in your own words:

22. Electronegativity
Compounds form because electrons are lost, gained, or shared between atoms.
The e- available to do this are called “Valence Electrons”.
They are the outermost electrons.
Electronegativity is the tendency of an atom to attract electrons towards itself.

23. Electronegativity
Electronegativity Increases UP and to the RIGHT

24. Electronegativity Follows the same trend as Ionization Energy. Why?
Smaller atoms are more electronegative due to the stronger force of attraction between their own e- and those belonging to other atoms.

25. Electronegativity Practice
Which of the following elements has the largest Electronegativity: Cs, N, Si, or K? Which has the smallest?
N, Cs

26. Electronegativity Practice
Of the elements Na, Rb, O, and Fr, which has the largest Electronegativity? Which has the smallest?
O, Fr

27. Electronegativity Practice
Arrange the following elements in order of increasing Electronegativity.
Al, Ba, N, C
Ba, Al, C, N

28. Electronegativity
Draw arrows like this on your handout and explain the Electronegativity Trend in your own words: