Name: _______________________________
Electron Configuration Modeling Activity
Background
Electron configurations for atoms and ions indicate properties of that atom or ion. Electron
configurations allow the behavior of the atom or ion to be predicted. Although an
electron’s precise location cannot be exactly determined at a point in time, the most
probable location for an electron can be identified in orbitals. How the electrons fill the
orbitals can be explained by the following rules:
1. Aufbau Principle: electrons occupy
orbitals of the lowest available
energy first before filling higher
energy orbitals
Energy Level
n= 1
2
3
4
5
nucleus
2. Hund’s Rule: electrons in the same sublevel will occupy empty orbitals before
double occupying an orbital
CORRECT— place one electron in each orbital for
2p before placing two electrons in each orbital.
1s
2s
2p
INCORRECT— placing two electrons in one
orbital while leaving empty orbitals in 2p.
1s
2s
2p
Atoms or ions that have completely full sublevels (no unpaired electrons) are the
most energetically stable arrangement of electrons. Those with exactly half-filled
sublevels are the next most stable.
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3. Pauli Exclusion Principle: two electrons in the same orbital
will have different magnetic spins (spin-up and spin-down)
1s
Correct
The magnetic properties can be
observed in real life for the predicted
electron configuration. If all orbitals
have been occupied with spin-up and
spin-down electrons, the atom or ion is
described as diamagnetic. This means it
will be repelled by a magnet (though
often only to a very small degree, not
noticeable by the human eye).
If there are orbitals that are not double
occupied with electrons, the atom or
ion is described as paramagnetic. This
means it will be attracted to a magnet.
North
1s
Incorrect
South
Magnetic
Field Lines
e-
e-
South
North
Spin + ½
Spin–up
Spin - ½
Spin–down
Pre-Activity Questions
1. Complete the following about orbitals.
Orbital Block
No. of
orbitals
No. Electrons each
sublevel can hold
Sketch or describe shape
s-block
p-block
d-block
2. In an electron configuration, which electrons are the valence electrons? How do these
electrons affect the properties of an element?
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Objective
To create electron configurations for various atoms and ions by following the Pauli
Exclusion Principle, Aufbau Principle, and Hund’s Rule, and to use these to predict
behavior of atoms and ions.
Materials
 18 flat marbles of one color
 18 flat marbles of a different color
 Orbital Diagram Modeling Sheet
Procedure
You are going to create electron configurations with the help of the Orbital Diagram
Modeling Sheet for a variety of atoms and ions following the rules laid out in the
Background section. The different colored flattened marbles represent electrons with
opposite spins. An orbital is “full” when it holds two electrons with opposite spins.
Complete the following steps for each atom or ion in the table below:
1. Identify the total number of electrons needed for the atom or ion.
2. Construct the requested electron configuration by placing the marbles to on the
Orbital Diagram Sheet. Double check that you have used the total number of
electrons needed for the atom or ion.
3. Write the electron configuration requested for each atom or ion to your data
collection.
4. Sketch the orbital diagram using arrows to represent spin-up and spin-down
electrons.
5. Be sure to get instructor approval when necessary (marked with a ).
No. of Total
Electrons
Atom / Ion
Instructor
Approval
Electron Configuration
He
Orbital Diagram
___
___
1s
___ ___ ___
___
___ ___ ___
___
3s
3p
4s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
2s
2p
___ ___ ___ ___ ___ ___ ___ ___
3d
4p
Be
Orbital Diagram
___
___
1s
2s
___ ___ ___ ___ ___ ___ ___ ___
3d
4p
N
Orbital Diagram
___
___
1s
2s
___ ___ ___ ___ ___ ___ ___ ___
3d
4p
O2–
Orbital Diagram
___
1s
___
2s
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3d
4p
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No. of Total
Electrons
Atom / Ion
Instructor
Approval
Electron Configuration
Ne
Orbital Diagram
___
___
1s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
2s
___ ___ ___ ___ ___ ___ ___ ___
3d
4p
Al
Orbital Diagram
___
___
1s
2s
___ ___ ___ ___ ___ ___ ___ ___
3d
4p
Al3+
Orbital Diagram
___
___
1s
2s
___ ___ ___ ___ ___ ___ ___ ___
3d
4p
S
Orbital Diagram
___
___
1s
2s
___ ___ ___ ___ ___ ___ ___ ___
3d
4p
-
Cl
Orbital Diagram
___
___
1s
2s
___ ___ ___ ___ ___ ___ ___ ___
3d
4p
Ar
Orbital Diagram
___
___
1s
2s
___ ___ ___ ___ ___ ___ ___ ___
3d
4p
V
Orbital Diagram
___
___
1s
2s
___ ___ ___ ___ ___ ___ ___ ___
3d
4p
Cr
Orbital Diagram
___
___
1s
2s
___ ___ ___ ___ ___ ___ ___ ___
3d
4p
Fe
Orbital Diagram
___
1s
___
2s
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3d
4p
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No. of Total
Electrons
Atom / Ion
Instructor
Approval
Electron Configuration
Fe3+
Orbital Diagram
___
___
1s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
___ ___ ___
___
___ ___ ___
___
2p
3s
3p
4s
2s
___ ___ ___ ___ ___ ___ ___ ___
3d
4p
Cu
Orbital Diagram
___
___
1s
2s
___ ___ ___ ___ ___ ___ ___ ___
3d
4p
As
Orbital Diagram
___
___
1s
2s
Br
___ ___ ___ ___ ___ ___ ___ ___
3d
4p
-
Orbital Diagram
___
___
1s
2s
___ ___ ___ ___ ___ ___ ___ ___
3d
4p
Kr
Orbital Diagram
___
1s
___
2s
___ ___ ___ ___ ___ ___ ___ ___
3d
4p
Analysis
1. What do you notice about the electron configurations you wrote for elements in the
same group, such as He, Ne, Ar, and Kr, or N and As?
2. Compare the electron configurations of Al, Al3+, O2– and Ne. Then compare Br- and Kr.
What patterns can be found to suggest why some elements tend to be found as ions
instead of neutral atoms? Explain these patterns in terms of the energetic stability of
the electron arrangements.
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3. Use your answer to the previous two questions to predict the charge that would form
on Ca and N if they were to form ions and explain your reasoning for your predictions.
4. A few of the atoms and ions in the table above did not perfectly follow the electron
configuration rules laid out in the background information. Explain why each of these
configurations was different from what the rules would predict.
5. Explain what is wrong with the following electron configurations. Then annotate the
configuration to correct the error.
a. 1s2 2s2 2p6 3s2 3p6 4s2 4d10 4p6
b. 1s2 2s2 2p6 3s3 3d5
6. Based on the orbital diagrams for the atoms and ions in this activity, list which
atoms/ions would be diamagnetic and which atoms/ions would be paramagnetic.
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Conclusion
Summarize what you have learned about how electrons behave in atoms and ions.
Include the following terms in your summary: Pauli Exclusion Principle, Aufbau Principle,
Hund’s Rule, valence electrons, energy levels, neutral atom, ion, electron configuration,
orbitals, stability, spin-up, spin-down, stability, diamagnetic, paramagnetic
Extension
1. Connecting properties of electron behavior to medical technology. Research how
magnetic resonance imaging (MRI) technology works and how it is used to diagnose
different diseases. Prepare a short powerpoint presentation, poster, or infographic
explaining your findings.
2. Exploring diamagnetism and paramagnetism. Research different forms of
magnetism, including (but not limited to) diamagnetism and paramagnetism.
Provide examples of different kinds of magnetic materials and how they can be
used. Prepare a short powerpoint presentation, poster, or infographic explaining
your findings.
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