Reactivity of Metals
Introduction:
The elements in the periodic table can be divided into two main groups: metals on
the left side and nonmetals on the right. Metals are the most numerous elements on the
Periodic Table. They have many properties with which most people are familiar, such as
high luster (shinning), ability to conduct heat and electricity well. Properties of metals
are dictated by the microstructure of mobile valence electrons attracting positively
charged metallic cations. Metals have some similar chemical properties. Metals tend to
have low ionization energy, hence relatively easy to lose valence electron(s) to form
cations in order to achieve electron configurations of noble gases. The tendency of metal
atom loses valence electron(s) determines chemical properties of metals. The usefulness
of metals in structural and other applications depends on their physical and chemical
properties. Although iron is the most common metal used in manufacturing and
construction, it must be protected against corrosion because iron rusts easily. Copper is
used in electrical wiring because it conducts electricity extremely well and resists
corrosion better than many metals. Gold is a highly valuable jewelry metal because it is
essentially unreactive. Chemically, metals have similarities in terms of losing valence
electrons, but the extent of how easy to lose those valence electrons differs due to variety
of reasons. How can we determine the relative reactivity of different metals?
Metals tend to be oxidized rather easily (which also means they are good reducing
agents). There are four general ways by which a metal can transfer electrons: (a) reaction
with water, (b) reaction with oxygen, (c) reaction with acids, and (d) reaction with other
metals. An example of the latter is the reaction of aluminum metal with copper nitrate to
produce aluminum nitrate and metallic copper.
2 Al(s) + 3 Cu(NO3)2(aq)
2 Al(NO3)3 (aq) + 3 Cu(s)
The activity series is a listing of the metals according to their reactivity as
reducing agents. The concept is that the more active a metal is in its elemental
(uncombined) state, the more likely it is to donate electrons to a positive ion (cation) in
solution and thus replace it in the solution. In the reaction above, aluminum is more
active than copper and thus replaces copper ions in solution. Reactions of this type are
sometimes also called single replacement reactions.
Hydrogen is usually included in the activity series. (In this case hydrogen is
considered a metal!) Metals more active than hydrogen are considered the "active"
metals, those less active than hydrogen are considered "inactive."
Purpose:
The student will investigate reactivity of metals in hydrochloric acid and aqueous
solutions of various ionic compounds.
Materials / Equipment:
Copper
Zinc
Magnesium
Aluminum
0.20 M AgNO3 aqueous solution
0.20 M Mg(NO3)2 aqueous solution
0.20 M CuCl2 aqueous solution
0.20 M Zn(NO3)2 aqueous solution
3.00 M HCl (hydrochloric acid)
microplate
spatula
Safety:
 Always wear safety glasses and apron in the chemistry lab.
 Never eat or drink in the chemistry lab.
 Avoid contact of all chemicals with eyes and all body tissues.
 Silver nitrate solution is toxic by ingestion and irritating to body tissue. It also
stains skin and clothing. Zinc nitrate solution is slightly toxic by ingestion and
corrosive to body tissue. Copper(II) chloride solution is slightly toxic by
ingestion; it is irritating to skin, eyes, and mucous membranes. Magnesium nitrate
solution is a body tissue irritant. 3M hydrochloric acid is corrosive and irritating
to skin.
 Always dispose waste chemicals according to approved practices.
Pre-lab Questions:
Read Pearson online textbook, Chapter 11 “Chemical Reactions”. Pay close attention to
the section about single-replacement reactions. In addition, use the following links to gain
further understanding of reactivity series (metals and halogens) and single-replacement
reactions.
http://en.wikipedia.org/wiki/Metal_reactivity
http://en.wikipedia.org/wiki/Single_displacement_reaction
1. How can you tell if a chemical change takes place? What are the major signs of
chemical reactions?
2. What is a reactivity series?
3. How many reactivity series are there? And what are they?
4. When salts of ionic compounds dissolve in water, what actually happened on the
ionic level?
5. Why water is a great solvent for many salts?
6. Draw models on the ionic/atomic/molecular level for metal, ionic compounds,
water, and ionic compounds dissolved in water.
7. What are the hypotheses for this lab?
Procedure:
Part A:
1. Use the microplate shown above. Each well should be used for one reaction. The
microplate is labeled as shown in the right half of the above image. The grid
system can be used to keep track of reactions.
2. Use distilled water to wash each cell carefully.
3. Each metal will be reacting with each aqueous solution. Fill wells in the first
column (A1, B1, C1, and D1) with one aqueous solution, the 2nd column with
another aqueous solution, and so on until 4 aqueous solutions are occupying 4
columns of wells.
4. Use the spatula to carefully transfer small amount of each metal into each well on
the same row. Metals are copper, zinc, aluminum and magnesium. For example,
wells in row A should be mixed with one copper, row B with zinc, row C with
aluminum, and row D with magnesium. Note: do not put too much metal into the
wells.
5. Observe carefully and record in details.
Part B:
6. There should be two columns of clean wells left on the microplate. Choose one of
the columns of clean wells, put in small amount of copper, zinc, magnesium, and
aluminum separately. Note: minimize the use of metals.
7. Put half-well full of 3.00 M HCl solution on top of the metals.
8. Observe carefully and record in details.
9. Dispose the contents according to instruction by the teacher.
10. Wash the microplate thoroughly first with tap water, then rinse 3 times with
distilled water.
Data Analysis:
 Organize data analyses in tabulated form.
 Attempt to find trends in the data in terms of reactivity.
Post-lab Questions:
1. Why is the instruction given at the beginning of the lab to wash the microplate
with distilled water?
2. Did all mixtures produce signs of chemical reactions? Summarize your
observations in a tabulated, easy to understand format in data analysis section.
3. What is the key difference among those aqueous solutions?
4. Which metal reacts with most of the aqueous solutions? Which metal reacts with
least?
5. Which metal reacts most vigorously with HCl? Which metal reacts the least?
6. Can the reactivity of metals (copper, zinc and magnesium) be ranked? Explain
your answer.
Extension Questions:
1. Write the balanced chemical equations with all reactions observed in the lab.
2. Can the reactivity of sodium, lithium, potassium, and magnesium metals ranked
using the approach utilized in this lab? Explain your answer.