Physical Science Institute
Summer 2013
Magnetic Attractions
Many pure substances, other than iron metal, are attracted to a strong magnetic field. These substances are said
to be paramagnetic. Substances that aren’t affected by strong magnetic fields, or are repelled, are said to be
diamagnetic. From experiments with electricity and magnetism, we know there is a connection between the magnetic
properties and the movement of electrons. In the quantum mechanical model, one of the energy states of electrons is
related to the electron’s spin (ms = -1/2 or +1/2). This electron spin produces a magnetic field with electrons spinning in
opposite directions having reverse magnetic poles.
In this investigation we will investigate the relationship between the arrangement of electrons in transition
metal ions and the degree of paramagnetic attraction to a magnet.
MATERIALS
1-dram vials labeled & filled with:
MnSO4, FeSO4, CoSO4, NiSO4, CuSO4, ZnSO4
Magnetic measuring device:
large neodymium magnet
small-scale calorimeter
paper, card stock
tongue depressors
balance electronic, + 0.001g or better
(6) periodic tables
(6) sheets of graph paper
(6) rulers
PRELAB
1) For each of the following transition elements give the orbital notation for the atom in its ground state:
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Physical Science Institute
Summer 2013
6s
5p
4d
5s
4p
3d
4s
Element or Ion
Symbol:
3p
3s
Mn
2p
2s
1s
2
Physical Science Institute
Summer 2013
6s
5p
4d
5s
4p
3d
4s
Element or Ion
Symbol:
3p
3s
Fe
2p
2s
1s
3
Physical Science Institute
Summer 2013
6s
5p
4d
5s
4p
3d
4s
Element or Ion
Symbol:
3p
3s
Co
2p
2s
1s
4
Physical Science Institute
Summer 2013
6s
5p
4d
5s
4p
3d
4s
Element or Ion
Symbol:
3p
3s
Ni
2p
2s
1s
5
Physical Science Institute
Summer 2013
6s
5p
4d
5s
4p
3d
4s
Element or Ion
Symbol:
3p
3s
Cu* note Cu is an exception to the
Aufbau principle
2p
2s
1s
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Physical Science Institute
Summer 2013
6s
5p
4d
5s
4p
3d
4s
Element or Ion
Symbol:
3p
3s
Zn
2p
2s
1s
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Physical Science Institute
Summer 2013
2) When these transition metals react to produce their chlorides, the 2+ ion is produced by the loss of two electrons
from the s-orbital in the highest principle energy level (n). For example, Mn would lose the two e- in the 4s orbital:
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Physical Science Institute
Summer 2013
6s
5p
4d
5s
4p
3d
4s
Element or Ion
Symbol:
3p
3s
Mn2+
2p
2s
1s
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Physical Science Institute
Summer 2013
For each of the following transition elements ions, give the orbital notation for the ion in its ground state:
6s
5p
4d
5s
4p
3d
4s
Element or Ion
Symbol:
3p
3s
Fe2+
2p
2s
1s
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Physical Science Institute
Summer 2013
6s
5p
4d
5s
4p
3d
4s
Element or Ion
Symbol:
3p
3s
Co
2p
2s
1s
11
2+
Physical Science Institute
Summer 2013
6s
5p
4d
5s
4p
3d
4s
Element or Ion
Symbol:
3p
3s
2+
Ni
2p
2s
1s
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Physical Science Institute
Summer 2013
6s
5p
4d
5s
4p
3d
4s
Element or Ion
Symbol:
3p
3s
Cu
2p
2s
1s
13
2+
Physical Science Institute
Summer 2013
6s
5p
4d
5s
4p
3d
4s
Element or Ion
Symbol:
3p
3s
Zn
2p
2s
1s
14
2+
Physical Science Institute
Summer 2013
3) For each ion in #2 give the number of unpaired electrons.
Mn2+ -
Ni2+-
Fe2+-
Cu2+-
Co2+-
Zn2+PROCEDURE
CAUTION: The neodymium-boron-iron magnet used in this experiment is very powerful but extremely brittle.
DO NOT test the magnet on the exposed metal at your laboratory station or bring
anything metallic near your magnet.
We will be testing the magnetic attraction of the chlorides (Cl-) of the ions in the pre-lab
assignment using the device in Figure 1.
1. Tare the balance with the magnet and foam block on the pan. Place one of the vials
being studied on the vial support and center the vial over the magnet. Record the
Figure 1
compound’s color and the value of the balance reading in you data table. Since the
compound is pulling up on the magnet, you should record the opposite sign (+ or -) shown on the balance.
2. Continue the experiment by testing the substance in the remaining vials in the same manner.
Data
Table 6.3
Metal Ion
(empty)
control
Mn2+
Fe2+
Co2+
Ni2+
Cu2+
Zn2+
Balance
reading
(grams)
Results and Conclusions
1. Prepare a graph plotting the balance reading in grams (y-axis) vs. the number of unpaired electrons in the metal ion
(x-axis).
2. What is the relationship between the strength of magnetic attraction and number of unpaired electrons? Explain this
trend in terms of electron spin.
3. The element vanadium (V) can have three common ion charges when in compounds, V3+, V4+ and V5+. List the
vanadium atom and its three common ions in order of increasing attraction to a magnet (lowest attraction on the left,
highest attraction on the right).
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Physical Science Institute
Summer 2013
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