1. Chapter Four Periodic Trends of the Elements

2. Section 4.1 Development of the Periodic Table

3. Development of the Periodic Table

4. Section 4.2 The Modern Periodic Table

5. Groups of the Periodic Table
Main group elements (1,2,13-17)
Transition Metals (3-12)
Noble Gases (18)
Lanthanides and Actinides
Elements in same GROUP exhibit similar chemical properties (due to their same number of valence electrons)

6. Groups of the Periodic Table

7. Section 4.3 Effective Nuclear Charge

8. Effective Nuclear Charge
Nuclear Charge (Z) is # of protons in the nucleus of an atom (atomic #)
Effective Nuclear Charge (Zeff) is the actual magnitude of positive charge “experienced” by an electron

9. Shielding Effect
A simultaneous phenomenon in which electrons are attracted to the positive nucleus while also repelled by other electrons
Electrons “shield” other electrons from the positive nucleus

10. Effective Nuclear Charge Trend
Increases steadily as you move across a period
Increases as you move down a group (but not as significant as when you move across a period)

11. Section 4.4 Periodic Trends

12. Atomic Radius

13. Atomic Radius

14. Atomic Radius

15. Group Quiz #1
For each pairing below, state which atom would have the larger atomic radius
Na or K
F or O
Xe or Kr

16. Ionization Energy
Minimum energy required to remove an electron from an element in the gas phase
Creation of a cation (positive ion)
First Ionization Energy (Easiest)
Second Ionization Energy (Hardest)
Etc

17. Ionization Energy

18. Electron Affinity
Energy RELEASED when an atom in the gas phase ACCEPTS an electron
Creation of an anion (negative ion)
Same general trend as ionization energy
Increases across a period (due to higher Zeff)
Decreases down a group (due to shielding)

19. Electron Affinity

20. Metallic Character
Increases from top to bottom and increases from right to left

21. Section 4.5 Electron Configuration of Ions

22. Electron Configuration of Ions
Elements want to be just like Noble Gases (very stable elements)
Full outer shells (8 v.e. or 2. v.e. w/ Helium)
They will lose or gain electrons to do this
Let’s look at Na and Cl

23. Electron Configuration of Ions
Write the electron configurations for the following ions:
Cr2+
Ti3+
Fe3+

24. Group Quiz #2 Write the electron configuration for the following ion:
Ag+
S2-

25. Section 4.6 Ionic Radius

26. Ionic Radius
When atoms lose electrons (become cations), radius decreases because of reduction in electron repulsions (and shielding)

27. Ionic Radius
When atoms gain electrons (become anions), radius increases because of the increased electron repulsion (spreads out)

28. Ionic Radius

29. Isoelectronic Series
Elements that are in an isoelectronic series all have the same electron configuration, but NOT the same size
Ex: Ca2+, K+, Ar, Cl-, S2-,P3-

30. Group Quiz #3
Name 2 elements you would expect to have similar properties to Sr
Arrange Ca, Sr, and Ba in order of increasing Ionization Energy
For each of the following pairs of elements, indicate which will have the greater electron affinity: Rb or Sr, C or N, O or F?
Identify the largest and smallest ion from the following: Mg2+, N3-, O2-, Na+, C4-