Quantum Atom

1
Quantum Atom
2
Quantum Mechanics

• Describes mathematically the properties of an
  electron
• Shows regions of probability of finding an
  electron

3
Quantum Numbers

• Orbital allowed energy state for an electron
• Principal Quantum Number (n) same as the Bohr
  energy level
• Also called shells
• Range from n1 to n7

4

• Azimuthal Number (l)
• Called subshells
• The maximum value of l is one less than n
• l0 s subshell (spherical)
• l1 p subshell (dumbbell)
• l2 d subshell (four lobes)
• l3 f subshell

5

• Magnetic Quantum Number (ml )
• These are the orbitals (hold 2 e- each)
• Range from l to l
• s ml 0 ( 1
  orbital)
• p ml -1, 0, 1 ( 3
  orbitals)
• d ml -2, -1, 0, 1, 2 (5
  orbitals)
• f ml -3, -2, -1, 0, 1, 2, 3 (7
  orbitals)

6
Order of Energy Levels

• Inner shell electrons shield outer electrons
  from the full positive effect of the nucleus
  screening effect
• Therefore different orbitals have different
  potential energies

7
(No Transcript)
8
Degenerate Orbitals

• Orbitals that have the same energies

9
Electron Spin

• Electron behaves as if it is spinning on its axis
• Fourth Quantum number (ms) is the spin number
• It can be either 1/2 or 1/2

10

• Spinning electrons produce magnetic fields

11
Pauli Exclusion Principle

• No two electrons can have the same set of four
  quantum numbers (n, l, ml, ms)
• If an orbital has two electrons in it, they must
  have different spins
• Electrons in the same orbital with different
  spins are called paired electrons

12
Configuration

• Arrangement of electrons in the atom
• Aufbau Principle orbitals fill in order of
  increasing energy

13
Orbital Diagram of Li ( 3 e-)

• 1s22s1

14
Orbital Diagram of B (5 e-)

• 1s22s22p1

15
Hunds Rule

• Electrons occupy degenerate orbits singly first

16
Orbital Diagram of C (6 e-)

• 1s22s22p2

17
Orbital Diagram of Ne (10 e-)

• Configuration 1s22s22p6

18
Valence Electrons

• Outer shell electrons
• Ones in the last main energy level
• ? K 1s22s22p63s23p64s1 1 valence e
• Fe 1s22s22p63s23p64s23d6 2 valence e