2. Warm-up
Write the abbreviated electron configurations for the elements below:
1) Chromium
2) Cesium
3) Chlorine
4) Cadmium

3. Warm-up Write the orbital notation for the elements below:
1) Vanadium
2) Sulfur
Write the abbreviated electron configurations for the elements below:
3) Vanadium
4) Sulfur
Write the full electron configuration for the element below:
5) Sulfur

4. Decoding the Periodic Table
Periodicity
Decoding the Periodic Table

5. Effective Nuclear Charge
The charge of the nucleus that is felt by the valence electrons
Symbol: Zeff
Zeff = atomic number (Z) - # of core e-

6. Effective Nuclear Charge

7. Effective Nuclear Charge
The charge of the nucleus that is felt by the valence electrons
Symbol: Zeff
Zeff = atomic number (Z) - # of core e-
What is the effective nuclear charge for each of the 8 main groups?

8. Effective Nuclear Charge

9. Periodicity Rules In the same period: In the same group:
Zeff increases going to the right
In the same group:
Distance between valence electrons and nucleus increases going down, so Zeff decreases going down within the same group

10. Disclaimer!
Transition metals are the worst…

11. Atomic Radius
The distance from the center of the nucleus to the valence electrons in an atom
When does atomic radius INCREASE in a period?
As Zeff DECREASES (valence electrons are held less tightly)
Moving to the LEFT
When does atomic radius INCREASE in a group?
As distance INCREASES
Moving DOWN

12. Atomic Radius

13. Atomic Radius

14. Electronegativity The ability of a neutral atom to gain an electron
When does electronegativity INCREASE in a period?
As Zeff INCREASES (new valence electron is attracted by a stronger positive charge)
Moving to the RIGHT
When does electronegativity INCREASE in a group?
As distance DECREASES (attractive force is stronger at smaller distances)
Moving UP

15. Electronegativity

16. Electronegativity

17. What is electronegativity?
Warm-up
What is electronegativity?

18. First Ionization Energy
The energy that it takes to remove one electron from a neutral atom
When does 1st IE INCREASE in a period?
As Zeff INCREASES (electron being removed is held more tightly)
Moving to the RIGHT
When does 1st IE INCREASE in a group?
As distance DECREASES (attractive force is stronger at smaller distances)
Moving UP

19. 1st Ionization Energy

20. 1st IE: Main Groups

21. First Ionization Energy

22. Ionic Radius vs Neutral Atom
Radius of a CATION (positively charged ion) is SMALLER that the neutral atom of that element
Radius of an ANION (negatively charged ion) is GREATER than the neutral atom of that element

23. Ionic Radius: Cations
The distance from the center of the nucleus to the valence electrons in a positively charged ion
When does cation radius INCREASE in a period?
Cation radius increases as the number of electrons lost DECREASES (remaining electrons are pulled closer to nucleus)
HINT: the fewer electrons lost, the greater the ionic radii
Cation radius INCREASES moving to the LEFT across a period
This is because fewer electrons are lost as you move left

24. Ionic Radius: Cations
The distance from the center of the nucleus to the valence electrons in a positively charged ion
When does cation radius INCREASE in a group?
Cation radius increases as distance from the nucleus INCREASES
So, cation radius increases moving DOWN a group

25. Ionic Radius: Anions
The distance from the center of the nucleus to the valence electrons in a negatively charged ion
When does anion radius INCREASE in a period?
As the number of electrons gained INCREASES (valence electrons held less tightly)
Moving to the LEFT
When does anion radius INCREASE in a group?
As distance INCREASES
Moving DOWN

26. Ionic Radius CATIONS ANIONS

27. NOTE:
Anions ALWAYS have larger ionic radii than cations!
Why is this?

28. Ionic Radius

29. Atomic Radius

30. Electronegativity

31. First Ionization Energy

32. Ionic Radius CATIONS ANIONS

33. Warm-Up Write the electron configuration for O2-
What wavelength of light is produced when an electron falls from n=5 to n=2?
What COLOR light is emitted when an electron falls from n=5 to n=2?

34. Warm-Up
1s22s22p6
434 nm
Blue

35. Periodic Trends
On your small periodic table draw and label the arrows for the following trends.
Atomic Radius
Electronegativity
1st Ionization Energy