1. Sections 7.4 – 7.5 Periodic Properties of Atoms and Ions

2. Periodic Properties In these sections… Trends in Orbital Energies
Atomic Size
Ionization Energy
Electron Affinity
Ion Electron Configuration and Size

3. Periodic Properties of the Elements
All atomic properties depend on energies of outermost orbitals.
Relative energies of outermost orbitals depend on their size and their effective nuclear charge.

4. Trends in Orbital Energies

5. Across a period, orbital energies decrease.

6. Why do energies decrease moving left-to-right?
Effective Nuclear Charge
Z* = Z - S

7. General Periodic Trends
Highest Occupied Orbital
smaller,
lower energy
larger,
high energy

8. Atomic Size
What does that mean?

9. Atomic Size: Trends

10. Ionization Energy What does that mean?
Atom(g)  Atom+(g) + e E = ionization energy

11. Ionization Energy: Trends I

12. Ionization Energy: Trends II

13. Why the breaks in the line?

14. Electron Affinity What does that mean?
Atom(g) + e-  Atom-(g) E = electron affinity
Trends:

15. Why is EA sometimes zero?

16. Ion Formation: Why do ions have the charges they do?

17. Cations vs. Anions

18. Electron Configurations of Cations

20. Transition Metal Cations: Lose s electrons first

21. Ion Size
In General:
Anions are big.
Cations are small.

22. Isoelectronic Species