F. Schifano, Department of Science
Bayonne High School, Bayonne NJ
Describe electrons in detail
Write electron configurations
Use electron configurations
The electron cloud is
composed of one or
more orbitals-regions where you are
likely to find electrons.
 Each orbital is divided
into one or more suborbitals.


Each sub-orbital can
hold two electrons.


Each type has a different shape and holds a
different number of electrons.
We represent the shape with a letter: s, p, d,
or f.
s
p
d
f
Shape
Sphere
Peanut
Dumbbells
Flowers
Sub-Orbitals
1
3
5
7
Electrons
2
6
10
14
The size of the orbital
is indicated with a
number.
 We refer to this
number as the energy
level.
 Nucleus = 0

Electrons will always
fill the most stable
orbital available.
 This is called the
Aufbau principle.
 The number of
electrons in an orbital
is represented with a
superscript.

Property
Represented By
Allowed Values
Size of Orbital
Number
1, 2, 3, 4, 5, 6, 7.
Shape of Orbital
Letter
s, p, d, f.
# e- In the Orbital
Superscript
Depends on Orbital Shape

Full sphere-shaped orbital on energy level
five

Peanut-shaped orbital on energy level two
with three electrons in it

4d7


Electrons will always fill the most stable
orbital available.
Orbitals closest to the nucleus are the most
stable.
 We also say they have the least potential energy.

Orbitals will always fill from the nucleus
outward.
 Remember, this represents filling from most
stable to least stable, lowest energy to highest
energy.

1s 2s  2p  3s  3p  4s  3d  4p 
5s  4d  5p  6s  4f  5d  6p  7s 
5f  6d  7p
Follow the arrows
diagonally.
 This picture is also in
your textbook on page
400.
 You should add it to
your formula sheet.


Figure out how many electrons you need to
configure.
 Remember: Atomic Number = p+ = e-

Write full orbitals in the usual order until
you run out of electrons.
 It’s OK if the last orbital isn’t full.
 Remember: shape of orbital determines capacity:
s = 2, p = 6, d = 10, and f =14.
Write the electron configurations of the
following elements:
Li
Cl
Fe
Kr
Cu
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What is an orbital?
What kinds of orbitals are there?
What is a sub-orbital?
How many sub-orbitals does a d orbital hold?
How many electrons does a d orbital hold?
How are orbitals arranged in space?
What controls the order in which electrons fill
orbitals?
What is the Aufbau principle?