1. Quantum Mechanical Model of the Atom

2. Progression of Atomic Theory

3. Bohr Model Energy levels 1st energy level can hold 2
2nd energy level can hold 8
3rd energy level can hold 8
Bohr Model Breaks down after 3rd energy level and no longer applies to Modern Quantum Mechanical Model of the Atom

4. Bohr Model for Hydrogen
Energy level of an electron
analogous to the rungs of a ladder
The electron cannot exist between energy levels, just like you can’t stand between rungs on a ladder
A quantum of energy is the amount of energy required to move an electron from one energy level to another
The Bohr model explained the emission spectrum of the hydrogen atom but did not always explain those of other elements.

5. The Quantum Mechanical Model
In 1926, Erwin Schrodinger derived an equation with 4quantum numbers that described the energy and position of the electrons in an atom
The 4 quantum numbers are used in the electron configuration which is a notation using energy levels and sublevels to show how the electrons are distributed within the atom.

6. Quantum Numbers Chem Saver p 23
Row # = Energy level or distance from nucleus
Possibilities 1 –7
7 Rows
Subshell
Possibilities are
s, p, d, or f
4 subshells 1 S
# electrons occupying this orbital
Possibilities are:
s: 1 or 2
p: 1-6
d: 1-10
f: 1-14

7. Energy Levels and Sublevels
The first energy level has only one type of orbital (sublevel) S
The second energy level has 2 types of orbitals
S and P
The third energy level has three types of orbitals
S, P and D
The fourth energy level has four types of orbitals
S, P, D and F
Successive energy levels follow the same pattern.
Relative energy: s < p < d < f

8. (sublevels available)
Principal Energy
Level (n=?)
Orbital Types
(sublevels available) 1 s 2 p 3 4

9. Orbital Shapes s orbital: (one possible orientation)

10. Orbital shapes
P orbital: ( three possible orientations)

11. Orbital shapes
d: orbital: ( five possible orientations)

12. Orbital shapes
f orbital: (seven possible orientations)

13. The Quantum Atom

14. (sublevels available)
Orbital Types
(sublevels available)
# of orbital's per level s 1 p 3 d 5 f 7

15. Total # of orbitals per P.E.L. (n2)
Principal Energy
Level (n=?)
Total # of orbitals per P.E.L. (n2) 1 2 3 4

16. (sublevels available) # of e’s per orbital type s 2 p 6 d 10 f 14

17. Total # of e’s per P.E.L. (2n2)
Principal Energy
Level (n=?)
Total # of e’s per P.E.L. (2n2) 1 2 3 4

18. Electron Configurations
Electrons fill the lowest energy levels first (H, Z=1) 4d
E N E R G Y 5s 4p 3d 4s 3p 3s 2p 2s 1s
1s1

19. Lewis Dot Structures
Lewis dot structures are shorthand to represent the valence electrons of an atom.
The structures are written as the element symbol surrounded by dots that represent the valence electrons.

20. Lewis Dot Structures E N E R G Y
Review Electron Configuration (H, Z=1) 4d
E N E R G Y 5s 4p 3d 4s 3p 3s 2p 2s 1s
1s1

21. Pauli Exclusion Principle
Fourth Quantum number is the Spin
Pauli Exclusion Principle
no two e- in an atom can have the same four quantum numbers.
each electron needs its own space.
Result – an orbital can hold a maximum of 2 electrons with opposite spin

22. Electron Configurations
Electrons fill the lowest energy levels first (He, Z=2) 4d
E N E R G Y 5s 4p 3d 4s 3p 3s 2p 2s 1s
1s2

23. Electron Configurations
Electrons fill the lowest energy levels first (Li, Z=3) 4d
E N E R G Y 5s 4p 3d 4s 3p 3s 2p 2s 1s
1s22s1

24. Electron Configurations
Electrons fill the lowest energy levels first (Be, Z=4) 4d
E N E R G Y 5s 4p 3d 4s 3p 3s 2p 2s 1s
1s22s2

25. Electron Configurations
Electrons fill the lowest energy levels first (B, Z=5) 4d
E N E R G Y 5s 4p 3d 4s 3p 3s 2p 2s 1s
1s22s22p1

26. Hund’s Rule
Don’t pair electrons in degenerate orbitals until necessary.
Unpaired electrons have the same spin.
Applies to p, d, and f orbitals 2p 3d

27. Electron Configurations
Electrons fill the lowest energy levels first
(C, Z=6) 4d
E N E R G Y 5s 4p 3d 4s 3p 3s 2p 2s 1s
1s22s22p2

28. Electron Configurations
Electrons fill the lowest energy levels first
(N, Z=7) 4d
E N E R G Y 5s 4p 3d 4s 3p 3s 2p 2s 1s
1s22s22p3

29. Electron Configurations
Electrons fill the lowest energy levels first
(O, Z=8) 4d
E N E R G Y 5s 4p 3d 4s 3p 3s 2p 2s 1s
1s22s22p4

30. Electron Configurations
Electrons fill the lowest energy levels first
(F, Z=9) 4d
E N E R G Y 5s 4p 3d 4s 3p 3s 2p 2s 1s
1s22s22p5

31. Electron Configurations
Electrons fill the lowest energy levels first
(Ne, Z=10) 4d
E N E R G Y 5s 4p 3d 4s 3p 3s 2p 2s 1s
1s22s22p6

32. Electron Configurations
Electrons fill the lowest energy levels first
(Na, Z=11) 4d
E N E R G Y 5s 4p 3d 4s 3p 3s 2p 2s 1s
1s22s22p63s1

33. Lewis Dot Structures Chem Saver p 24
Lewis dot structures are shorthand to represent the valence electrons of an atom.
The structures are written as the element symbol surrounded by dots that represent the valence electrons.

34. Electron Configurations
Your Turn: Try Krypton (Kr, Z=36) 4d
E N E R G Y 5s 4p 3d 4s 3p 3s 2p 2s 1s

35. Electron Configurations
Electrons fill the lowest energy levels first (Ca, Z=20) 4d
E N E R G Y 5s 4p 3d 4s 3p 3s 2p 2s 1s
1s22s22p63s23p64s2

36. An internet program about electron configurations is:
(Just click on the above link)

37. Diagonal Rule for Writing Configurations and Practice Chem Saver p 23

38. The relation between orbital filling and the periodic table
Chem Saver p 23
ns1
np1
n-1d1
n-2f1

39. In your composition notebook complete, Z=11 to 54 odd only
In your composition notebook complete, Z=11 to 54 odd only. Be sure to show the electron configuration short hand notation and the Lewis dot structure for each.

40. Electron Configuration on the Periodic Table
The elements in the same family groups on the periodic table have similar physical and chemical properties
The elements in the same family groups also tend to form similar types of compounds with other elements
This is because the elements in the same family groups have the same number of electrons in the outer energy level

41. Short Hand noble gas configurations