1. Quantum Numbers and Shapes
Chapter 10

2. principal energy level sublevels orbital's electron spin
Chpt 10 – Quantum Numbers
An orbital is an orientation in space, so a series of steps (quantum numbers) are used to describe various properties of the orbital. The steps are:
principal energy level
sublevels
orbital's
electron spin

3. principal energy level
Chpt 10 – Quantum Numbers
principal energy level
Has whole numbers (1, 2, 3,…) that relate to the size and energy of the orbital.
The orbital becomes larger with an increase in the principle energy level number, thus the electron spends more time away from the nucleus.
The energy is higher because the electron is not as tightly bound by the nucleus.

4. “s” sublevels *contains 1 orbital “p” sublevels *contains 3 orbitals
Chpt 10 – Quantum Numbers
sublevel’s
“s” sublevels *contains 1 orbital
“p” sublevels *contains 3 orbitals
“d” sublevels *contains 5 orbitals
“f” sublevels *contains 7 orbitals

5. Chpt 10 – Quantum Numbers
orbital’s
Relates to the orientation of the orbital in space. (Example: (p- sublevel) x, y, z)
An orbital is the area that there is a 90% chance of finding the electron in that area.
The orbital’s of different sublevels have different shapes based upon mathematical models.

6. S orbitals are spherical in shape
90% boundary:
Inside this lies
90% of the probability
nodes

7. P-orbitals
Node at nucleus

8. The Boundary Surface Representations of All Three 2p Orbitals

9. The Boundary Surfaces of All of the 3d Orbitals

10. Representation of the 4f Orbitals in Terms of Their Boundary Surfaces

11. THE MULTI-ELECTRON ATOM ENERGY LEVEL DIAGRAM
Remember the energies are < 0 1s E 2s 2p 3s 3p 3d 4s 4p 5s 4d

12. Sublevels and orbitals based on the Periodic Table

13. Alternative Periodic Table

14. ELECTRONIC CONFIGURATIONS
THE BUILDING-UP PRINCIPLE.
GROUND STATE
lowest energy electronic configuration
assign electrons to orbitals one at a time
Electrons go into the available orbital of lowest energy.
At least one electron is in each orbital of a sublevel before a second electron is added to the orbital.
A maximum of two electrons per orbital.

15. Order of Filling Orbitals

16. THE AUFBAU (BUILDING-UP) PRINCIPLE:
electrons are added to hydrogen-like atomic orbitals in order of increasing energy 1s E 2s 2p 3s 3p 3d 4s 4p 5s 4d
The electron configuration of any atom or ion…....
can be represented by an orbital diagram

17.    ORBITAL DIAGRAM Hydrogen has its one electron in the 1s orbital:
1s 2s 2p H:
1s1 
Helium has two electrons:
both occupy the 1s orbital
Pauli principle
with opposite spins:
1s 2s 2p
He:  
1s2
1s 2s 2p
He:

18. ORBITAL DIAGRAM
Hydrogen has its one electron in the 1s orbital:
1s 2s 2p H:
1s1 
Helium has two electrons:
both occupy the 1s orbital
Pauli principle
with opposite spins:
1s 2s 2p
He:  
1s2
helium ground state
Helium can also exist in an excited state such as:
1s 2s 2p
He: 
1s12s1 
Now onto the next atoms

19. Lithium has three electrons, so it must use the 2s orbital:
Beryllium has four electrons, which fill both the 1s and 2s orbitals:
Boron’s five electrons fill the 1s and 2s orbitals, and begin to fill the 2p orbitals. Since all three are degenerate, the order in which they are filled does not matter.
1s 2s 2p
Li: 1s22s1
1s 2s 2p
Be: 1s2 2s2
1s 2s 2p
B: 1s22s22p1

20. CARBON Z=6 A CHOICE OR How can we decide????? 1s 2s 2p C: 1s22s22p2

21. ELECTRONS OCCUPY DEGENERATE ORBITALS SEPARATELY
HUND’S RULE
FOR THE GROUND STATE
ELECTRONS OCCUPY DEGENERATE ORBITALS SEPARATELY
THE SPINS ARE PARALLEL
SO FOR CARBON THE GROUND STATE IS
1s 2s 2p
C: 1s22s22p2

22. ENERGY LEVEL DIAGRAM FOR A MULTI-ELECTRON ATOM
BROMINE ELECTRONIC CONFIGURATION 1s E 2s 2p 3s 3p 3d 4s 4p 5s 4d                 
[Ar] 4s23d104p5 

23. Every element in a group has
The valence electron configuration of the elements in the periodic table repeat periodically!
H He
1s s2
Li Be B C N O F Ne
2s1 2s p1 2p2 2p3 2p4 2p5 2p6
Na Mg Al Si P S Cl Ar
3s1 3s p1 3p2 3p3 3p4 3p5 3p6
Every element in a group has
the same valence electron configuration!

24. Chpt 10 – Quantum Numbers Electron Spin
The concept of electron spin was developed to account for a magnetic moment.
Classical physics indicates that a moving (spinning) charge produces a magnetic moment (field).
Opposite spins produce opposite magnetic fields.

25. Electron Spin

26. This 2-valued electron spin can be shown in an experiment
In silver (and many other atoms) there is one more “spin up” electron than
“spin down” or vice versa. This means that an atom of silver can interact with a
magnetic field and be deflected up or down, depending on which type of spin
is in excess.

27. Transition Metal Demonstration
The chromium, manganese, and iron ions will exhibit magnetic character because of the high number of unpaired electrons in the 3d orbitals.
Will zinc show any magnetic character?