The Quantum Mechanical model
• It is based on the energy and possible location of an electron.
• how likely it is to find an electron is described in terms of probability. (ie.
Propeller blades)
• Based on work done by Shrodinger…

Atomic Orbitals
• The energy levels of electrons are labeled by principal quantum numbers (n)
• Each energy sublevel corresponds to an orbital of a different shape, which describes where the electron is likely to be found.

Atomic Orbitals

Quantum Mechanics
•
Orbital ( “ electron cloud ” )
– Region in space where there is 90% probability of finding an electron
90% probability of finding the electron
40
30
20
10
0
0
Electron Probability vs. Distance
50 100 150
Distance from the Nucleus (pm)
200 250
Orbital
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Shapes of s, p, and d-Orbitals
s orbital
p orbitals
d orbitals

Please write this in your notes.
Orbital s p d f
Shape
Spherical
Figure-8, dumbbells
Double figure-8s and belted
Don’t worry!
No. per sublevel
1
3
5
7

The Shapes of the s, p, and d Orbitals
Sketch these in your notes

Electron Orbitals:
Electron orbitals
Equivalent
Electron shells
(a) 1s orbital (b) 2s and 2p orbitals
1999, Addison, Wesley, Longman, Inc. c) Neon Ne-10: 1s, 2s and 2p

Copyright © 2006 Pearson Benjamin Cummings. All rights reserved.

1s Orbital
• Sphere around the nucleus
The one tells you that the electron is in the orbital closest to the nucleus
• S tells you about the shape

2s Orbital
• Similar to 1s except the electron is most likely in the region farther from the nucleus

p Orbitals
• At the first energy level there is only the 1s orbital, after the second energy level there are 2p orbitals
• Look like dumbbells
• In the three directions

Remember….
MAX NUMBER OF ELECTRONS
IN AN ENERGY LEVEL
ENERGY LEVEL MAX # OF ELECTRONS
3
4
1
2
5
2
8
18
32
50

Energy Level Sub-level Type of sub d f s p
Sphere
Dumbbell
4-Lobed
6-8 Lobed
10
14
2
6
# of
Orbitals
1
3
5
7