Physical Science Institute
Summer 2013
Magnetic Attractions
MATERIALS
Per 2 groups of 3 participants:
 1-dram vials labeled & filled with:
o MnSO4, FeSO4, CoSO4, NiSO4, CuSO4, ZnSO4, & an empty vial as a control
 Magnetic measuring device:
o large neodymium magnet
o small-scale calorimeter
o paper, card stock
o tongue depressors
o balance electronic, + 0.001g or better
Tongue depressors
Periodic Tables
Paper, card stock
Iron(II)sulfate, 100 g
Copper(II)sulfate, 100 g
Manganese(II)sulfate, 100 g
Cobalt(II)sulfate, 100 g
Nickel(II)sulfate, 100 g
Zinc sulfate, 100 g
Vial, glass, 1 dram
Neodymium magnet
Calorimeters, small-scale
Balance, top-loading
Flinn
Flinn
Flinn
Flinn
Flinn
Flinn
Fisher
Arbor Sci
Flinn
Fisher
F0031
C0102
M0030
C0073
N0011
Z0023
03-343-6C
P8-1124
AP5928
S94792K
NOTES
1) To set up the magnetic attraction device you’ll need an electronic balance with a minimum precision of 0.001g. The
diagram below shows the set up for the device.
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Physical Science Institute
Summer 2013
To determine the height of the collar, place the spacer on the balance pan and then place the magnet on the spacer.
Slide the two together to the edge of the balance pan and measure the distance from the top of the balance body to the
top of the magnet. Add 1-2mm(1/16”) to your measure to determine the height of the collar. Cut an 81/2” x 11” piece of
heavy paper or lightweight cardboard into 8 1/2” x the height you just calculated. Overlap the two pieces of paper by 1”
and tape the two together being certain they are flush at the bottom. Wrap the two attached pieces around the balance
pan and loosen the ring created until an approximate ¼” gap exists between the cardboard and the pan. Tape the two
together to form the collar. MAKE SURE THE COLLAR DOES NOT TOUCH THE BALANCE PAN.
For the vial support:
Lay two tongue depressors on a flat surface and separate them by 9-10 cm(3/8”). A popsicle stick is a perfect spacer
here. Measure the width of this setup and cut another tongue depressor or popsicle stick to prepare the two cross
members. Add a drop of superglue to each piece and put a book or other heavy object on it until the glue dries.
Adapted from “Electron Configurations & Magnetic Properties of Matter”, Walter Rohr, Flinn Scientific Foundation Summer Chemistry Workshop 2002
2) Six vials are filled with each of the salts. Add the salt, tap the vial on the table to minimize air pockets, add more salt,
and tap on table until the vial is filled. Tighten the cap firmly to seal the vial.
CAUTION: Some of the salts used are corrosive or possible carcinogens. Wash your hands and work in a well-ventilated
area when filling the vials.
3) If participants are getting poor results, check the space between the vial and the magnet. If there is too much space (>
¼”) the attraction isn’t enough to measure with the scale.
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Physical Science Institute
Summer 2013
Pre-Laboratory Activity:
1) For each of the following transition elements give the orbital notation for the atom in its ground state:
NOTE: Cu is an exception to the Aufbau Principle and should be written on the board for participants
Mn
1s
2s
2p
3s
3p
4s
3d
2s
2p
3s
3p
4s
3d
2s
2p
3s
3p
4s
3d
2s
2p
3s
3p
4s
3d
2s
2p
3s
3p
4s
3d
2s
2p
3s
3p
4s
3d
Fe
1s
Co
1s
Ni
1s
Cu
1s
Zn
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 electrons from the
s-orbital in the highest principle energy level (n). For each of the following transition elements ions, give the orbital
notation for the ion in its ground state:
Mn2+
1s
2s
2p
3s
3p
4s
3d
2s
2p
3s
3p
4s
3d
2s
2p
3s
3p
4s
3d
2s
2p
3s
3p
4s
3d
2s
2p
3s
3p
4s
3d
2s
2p
3s
3p
4s
3d
Fe2+
1s
Co2+
1s
Ni
1s
Cu
1s
Zn
1s
3) For each ion in #2 give the number of unpaired electrons.
Metal ion
Unpaired
electrons
Mn+2
Fe+2
Co+2
Ni+2
Cu+2
Zn+2
5
4
3
2
1
0
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Physical Science Institute
Summer 2013
Data
Table 6.3
Metal Ion
Balance
reading
(grams)
(empty)
control
Mn+2
Fe+2
Co+2
Ni+2
Cu+2
Zn+2
0.00
1.13
0.71
0.53
0.26
0.09
-0.01
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).
The graph of magnetic attraction vs. number of unpaired electrons will not be a straight line.
Magnetic Attraction vs. Number of
Unpaired Electrons
1.2
1
balance reading (g)
0.8
0.6
0.4
0.2
0
0
-0.2
1
2
3
4
5
6
Number of unpaired electrons
2. What is the relationship between the strength of magnetic attraction and number of unpaired electrons? Explain this
trend in terms of electron spin.
A pair of electrons contained in the same atomic orbital will have opposite spins. The opposite spins of
produce opposite magnetic fields. The magnetic field of one electron is “canceled out” by the magnetic field of the
other paired electron.
3. The element vanadium (V) can have three common ion charges when in compounds, V+3, V+4 and V+5. 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).
lowest - V+5 , V+4, V+3, V - highest
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