Quantum Mechanical Model

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Quantum Mechanical Model
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Limitations of the Bohr Model
Only works for atoms with 1 e-
e- behave like waves instead of particles.
e- DO NOT travel in fixed paths around the
nucleus!!!
e- found in certain regions around the nucleus!
These regions (orbitals) are based on probability
where e- can be found.
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It is not possible to determine the location
momentum of an e- at the same time (Heisenburg
Uncertainty Principle).
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Quantum Numbers

• Four Quantum Numbers
• Specify the address of each electron in an atom

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Quantum Numbers

• 1. Principal Quantum Number ( n )
• Energy level
• Size of the orbital
• n2 of orbitals in the energy level

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Quantum Numbers

• 2. Angular Momentum Quantum ( l )
• Energy sublevel
• Shape of the orbital

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Quantum Numbers

• n of sublevels per level
• n2 of orbitals per level
• Sublevel sets 1 s, 3 p, 5 d, 7 f

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Quantum Numbers

• 3. Magnetic Quantum Number ( ml )
• Orientation of orbital
• Specifies the exact orbitalwithin each sublevel

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Quantum Numbers
px
py
pz
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Quantum Numbers

• Orbitals combine to form a spherical shape.

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Quantum Numbers

• 4. Spin Quantum Number ( ms )
• Electron spin ? ½ or -½
• An orbital can hold 2 electrons that spin in
  opposite directions.

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Quantum Numbers

• Pauli Exclusion Principle
• No two electrons in an atom can have the same 4
  quantum numbers.
• Each e- has a unique address

1. Principal ? 2. Ang. Mom. ? 3. Magnetic
? 4. Spin ?
energy level sublevel (s,p,d,f) orbital electron
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If you recall
Each energy level consists of one or more
sublevels.
s lt p lt d lt f
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Quantum Mechanical Model
There is a maximum of e- that can occupy each
sublevel.
As previously stated, e- are located in regions
(orbitals) where they have the highest
probability of being found!