1. Orbitals and Quantum Numbers(

2. Drill
If the frequency of radiation is x Hz. What is the wavelength of light in cm?

3. Objectives iWBAT Distinguish between the 4 quantum numbers.
describe the quantum numbers n, l, and ml used to define an orbital in an atom, and list the limitations placed on the values each may have.
Assign quantum numbers to specific electrons in atoms

4. What is an orbital?
An orbital is an allowed energy state of an electron in the quantum-mechanical model of the atom
the term orbital is also used to describe the spatial distribution of the electron.
Defined by the values of 4 quantum numbers: n, l, and ml , ms

5. 4 Quantum Numbers
Reminder: quantum numbers specify the properties of atomic orbitals and the properties of electrons in orbitals

6. Principal Quantum Number “n”
The principal quantum number (n) indicates the main energy level occupied by the electron
n can have integral values of 1, 2, 3, etc.

7. The Large Numbers Represent the Principal Quantum Numbers

9. Azimuthal Quantum Number
The angular momentum (or azimuthal) quantum number (symbolized by “l “) indicates the shape of the orbital
“l “ can take on integral values from
0 to n -1
for each value of n
L is Mistral font

10. Which sublevel does each value of “l ” represent?
Value of l letter used
0 s
1 p
2 d
3 f

11. http://chemwiki. ucdavis

12. http://hyperphysics. phy-astr. gsu. edu/hbase/quantum/imgqua/hydco5

13. Magnetic Quantum Number
The magnetic quantum number ( ml ) describes the orientation of the orbital in space
It can take on values from “l to –l ”
For example:
If “l ” is 2 then ml could be 2, 1, 0, -1, -2

14. Electron Spin Quantum Number
Electron Spin Quantum Number (ms )
This number indicates the two fundamental spin states of an electron in an orbital
This quantum number can only have two possible values, + ½ or - ½

16. Pauli Exclusion Principle
states that no two electrons in an atom can have the same set of 4 quantum numbers n, l, ml, and ms

17. http://www. chemistryland

20. Practice Problem #1 For n=4, what are the possible values of l ?
Answer on next slide.

21. Answer
l = 0,1,2,3
(what do these values correspond to?)

22. Practice Problem #2 For l =2, what are the possible values of ml ?
Answer on next slide.

23. Answer
ml = 2,1,0,-1,-2
(what do these values correspond to?)

24. Can an e- be described by the following set of quantum numbers?
n=2, l=1, ml=-1
All quantum numbers are allowed values

25. Can an e- be described by the following set of quantum numbers?
n=1, l=1, ml=+1
Not possible.
The value of l must be less than the value
of n.

26. Can an e- be described by the following set of quantum numbers?
n=7, l=3, ml=+3
All the quantum numbers are allowed
values.

27. Can an e- be described by the following set of quantum numbers?
n=3, l=1, ml=-3
Not possible.
The value of ml must be in the range
-l to +l

28. Can an e- be described by the following set of quantum numbers?
n=2, l=1, ml=-2
n=3, l=2, ml=+2
n=4, l=3, ml=+3
n=5, l=2, ml=+3

29. Replace the ? Mark with an appropriate quantum number.
n=3, l=1, ml=?
n=4, l=?, ml=-2
n=?, l=3, ml=?