Atomic Structure

1
Atomic Structure

• Quantum Numbers

2
Quantum Numbers

• specify the properties of orbitals and of
  electrons in orbitals
• the first three numbers describe
• main energy level (n)
• Shape (l)
• Orientation (ml)
• 4th describes spin of electron (ms)

3
1st Quantum Number (n)

• main energy level occupied by electron
• values are all positive whole integers
  (1,2,3,)
• As it increases, the electron
• has more energy
• is farther from nucleus
• the total number of orbitals in a level is equal
  to n2

4
1st Quantum Number (n)

• n of orbitals
• 1 1
• 2 4
• 3 9
• 4 16

5
2nd Quantum Number (l)

• the shape of the orbital (sublevel)
• possible shapes energy level
• 4th energy level has 4 possible shapes
• possible values 0 to n-1
• s 0
• p 1
• d 2
• f 3

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2nd Quantum Number
Level
Sublevels
Sublevels
0 1 2
3
0 1 2

0 1
0
7
3rd Quantum Number (ml)

• the position of an orbital around the nucleus (x,
  y, or z direction)
• has values from l ? -l
• each orbital holds maximum of 2 electrons

8
4th Quantum Number (ms)

• the spin state of the electron
• only 2 possible directions
• only 2 possible values ½ and -½
• paired electrons must
• have opposite spins

-1/2 1/2
9
Connection to Configurations

• Draw out the orbital notation for the last
  sublevel filled in an atom
• Circle the last electron inserted in that
  sublevel
• Find the four quantum numbers for that electron

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Example 1

• What are the 4 quantum numbers for the electron
  of highest energy in nitrogen?

11
Example 2

• What are the 4 quantum numbers for the electron
  of highest energy in sulfur?

12
Example 2

• What are the 4 quantum numbers for the electron
  of highest energy in iron?

13
Example 4

• What are the 4 quantum numbers for the electron
  of highest energy in calcium?