Transcript Unit 3: quantum numbers powerpoint

Quantum Numbers
At the conclusion of our time
together, you should be able to:
 List and define the 4
principles that are part of
quantum numbers.
 List and define each of the 4
quantum numbers.
 Give the quantum number
for every electron of every
atom on the periodic table.
Principal Quantum Number - n
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Symbol = n
Represents the main energy level of the electron
and its distance from the nucleus
Current values of 1-7.
Also called the shell.
# of total electrons per energy= 2n2
 If n=1, then the first energy level can hold 2
electrons.
 n= 2, 2nd level can hold 8 electrons
 3rd? & 4th ?
The Second Quantum Number - l
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Angular momentum quantum number.
This number describes sublevels (orbital),
shapes of these sublevels.
Sublevels are named s, p, d, f.
Each sublevel has a unique shape.
The number of sublevels per energy level= n2
 1st level only has one sublevel
 2nd level has 4 sublevels
Shape of the “s” Orbital
•s for "Sphere": the simplest shape.
•Each energy level has one "s" orbital within that
level.
Shapes of the “p” Orbitals
•p for "Peanut/Petal": a more complex shape that
occurs at energy levels 2 and above.
Shapes of the “d” Orbitals
• d for "Double Peanut/Petal": a complex shape
occurring at energy levels 3 and above
Shapes of the “f” Orbitals
•f for "Flower": bizarre-shaped orbitals for
electrons of very large atoms
The Second Quantum Number - l
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Values are 0 to (n-1)
Therefore:
 For s, l = 0
 For p, l = 1
 For d, l = 2
 For f, l = 3
The Third Quantum Number - m
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Magnetic quantum number
This number describes orientations (x, y, z
plane) of the orbitals that each sublevel can
have.
s has one orientation
p has three orientations (px , py , pz )
d has five orientations
f has 7 orientations.
Values are –l to 0 to +l
The Fourth Quantum Number - s
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This number describes the spin of the electrons
in an orbital.
There can be two electrons in each orbital as
long as they are spinning in opposite directions.
Values are +1/2 = clockwise spin (up)
-1/2 = counterclockwise spin (down)
The 4 Blocks of the Periodic Table