Periodic Properties of the Elements
PRELAB ASSINGMENT
Read the entire laboratory write up. Write an objective, briefly describe any hazards associated
with this lab, and answer the following questions before coming to lab. Read the entire laboratory write
up before answering the prelab questions.
1. List all the alkali metals (Group IA) except Fr and list each metal’s electron configuration using
orbital box notation (you may use noble gas abbreviation or condensed form for elements larger
than Ne), atomic and ionic radii, first ionization energy, and electron affinity. Chapter 7 and
Appendix 3 of your textbook are good places to look for these values.
2. Define the terms ionization energy and electron affinity.
3. Which of the alkali metals would you predict to lose its outer electron most readily and briefly
explain why?
4. List all the halogens (Group VIIA) except At and list each metal’s electron configuration using
orbital box notation (you may use noble gas notation for elements larger than Ne), atomic and
ionic radii, first ionization energy, and electron affinity. Chapter 7 and Appendix 3 of your
textbook are good places to look for these values.
5. Which halogen would you predict to most readily gain an electron and briefly explain why?
INTRODUCTION
The purpose of this exercise is to explore the chemistry of a few of the elements. You will look for trends
in the chemical and physical properties of the elements as a function of their position within a period or
group on the periodic table.
PROCEDURE
General Directions
1. Notice that this lab involves handling concentrated acids and an open flame. Thus safety glasses
must be worn at all times. Also, you will be generating hydrogen gas during several reactions.
Hydrogen gas is explosive and you should never conduct a reaction that could produce hydrogen
near an open flame. Hydrogen gas can be generated whenever you add a metal to an acidic
solution. Be alert to your surroundings at all times. Follow all procedures closely and carefully.
2. Use distilled water whenever water is called for.
3. Record your observations in your laboratory notebook, following the layout in the “Observations
and Data” section of this laboratory exercise. Some reactions will occur immediately, some
reactions will take longer to occur, and some will never occur. Recall that color changes, gas
evolution, changes in temperature, formation of a solid, or disappearance of a solid may all
indicate a chemical reaction has occurred. Note any and all observations that may indicate
whether or not a chemical reaction occurred in your lab notebook. Especially look for and
record similarities and differences between elements within the same period or group and
between elements from different periods or groups of the periodic table.
4. Answer the questions at the end of this laboratory exercise, including writing balanced chemical
equations for the reactions that occurred, based on your observations. If no reaction
occurred, write “NR” in the appropriate space. Examples for some reactions are included in
the lab write up to get you started.
A. Group IA Elements: Alkali Metals – Sodium and Potassium
a) Reaction(s) with oxygen
1. Using a clean, dry watch glass, get a small piece of metallic sodium (stored under mineral
oil).
2. Cut the piece of sodium with the end of a spatula and carefully observe what happens as the
freshly cut surface is exposed to the atmosphere.
b) Reaction(s) with water
3. Drop the small piece of sodium into approximately 50 mL of distilled water in a 250 mL
beaker. Keep valuable and flammable items away from the beaker. DO NOT lean over the
beaker. Test the resulting solution with litmus paper and determine if the solution is acidic or
basic.
4. Record all of your observations in your laboratory notebook.
5. Repeat steps 1-3 using a small piece of metallic potassium. . Keep valuable and flammable
items away from the beaker. DO NOT lean over the beaker. Again, record all of your
observations in your laboratory notebook.
B. Group IIA Elements: Alkaline Earth Metals – Magnesium and Calcium
a) Reaction(s) with oxygen
1. Hold approximately 1 inch of magnesium ribbon with crucible tongs and, while keeping the
metal at arm’s length, hold the metal in a Bunsen burner flame. Do not look directly at the
magnesium when it ignites. Record your observations and write the balanced equation for the
chemical reaction that occurs in your laboratory notebook.
2. Repeat step number 1 using a small piece of calcium. This works best if your piece of
calcium is thin. You will have to hold the calcium in the flame quite a bit longer than you did
magnesium before the reaction will take place. Also, you must hold the calcium in the hottest
region of the flame (the outer region of the bright blue inner cone). Record your observations
and write the balanced equation in your laboratory notebook.
b) Reaction(s) with water
3. Scratch a small piece of magnesium ribbon with a spatula. Put approximately 5 mL of water
in a test tube and add a couple of drops of phenolphthalein indicator to the test tube.
Phenolphthalein is an acid/base indicator that turns pink at pH values greater than
approximately 9.2-9.7 and remains clear at pH values less than approximately 9.2-9.7. Place
the scratched piece of magnesium ribbon in the test tube and record your observations in your
laboratory notebook.
4. Repeat step 3 using a small piece of calcium. Again record your observations and write
balanced chemical reactions in your laboratory notebook. Note the difference between the
reactions of Group IA and Group IIA metals with water.
c) Reaction(s) with 6 M HCl
5. Place approximately 5 mL (approximately ½ inch) of 6 M HCl in a clean test tube. Carefully
drop a small piece of magnesium into one test tube. Inverted an empty test tube over the tube
in which the reaction is occurring to collect the gas being produced. Immediately move the
inverted test tube so the open end is above a Bunsen burner flame. Record your observations
in your laboratory notebook.
6. Repeat step five using a small piece of calcium. Write balanced equations for the chemical
reactions that occurred in your laboratory notebook.
C. Group IIIA Elements – Aluminum
a) Reaction(s) with oxygen
1. Hold a small piece of aluminum metal with crucibles tongs and insert it into a Bunsen burner
flame. Record your observations in your laboratory notebook.
b) Reactions with water and 6 M HCl
2. Place 4-5 strips of aluminum in a test tube containing water and another 4-5 strips of
aluminum in a test tube containing 6 M HCl. Record you observations and write balanced
equations for all reactions that occurred.
D. Group IVA Elements – Carbon
a) Reactions with water and 6 M HCl
1. Place about ¼ inch of powdered carbon on the end of a spatula into a test tube containing
approximately 5 mL of water and another ¼ inch of powdered carbon on the end of a spatula
into another test tube containing approximately 5 mL of 6 M HCl. Tap the bottom of each
test tube with a spatula. Wait 5 minutes; then again tap each tube with a spatula. Record
your observations in your laboratory notebook.
E. Group B Elements – Transition Metals – Copper, and Zinc
a) Reaction(s) with water
1. Place approximately 5 mL of water in each of three test tubes. Place a piece of copper in one
test tube and zinc in a second test tube. Tap each tube. Record your observations in your
laboratory notebook.
b) Reaction(s) with 6 M HCl
2. Repeat step 1 using two clean test tubes containing approximately 2 mL of 6 M HCl and a
sample of each metal. Record your observations in your laboratory notebook and write
balanced equations for any reactions that occurred.
3. Invert an empty test tube over the tube in which the reaction between zinc and 6 M HCl is
occurring to collect the gas being produced. Immediately move the inverted test tube so the
open end is above a Bunsen burner flame. Record your observations in your laboratory
notebook.
OBSERVATIONS AND DATA
A. Group IA Elements: Observations and balanced equations.
Sodium + oxygen
4Na(s) + O2(g)  2Na2O(s)
Potassium + oxygen
Sodium + water (consider litmus paper results)
2Na(s) + 2H2O(l)  2NaOH(aq) + H2(g)
Potassium + water (consider litmus paper results)
B. Group IIA Elements: Observations and balanced equations.
Magnesium + oxygen
2Mg(s) + O2(g)  2MgO(s)
Calcium + oxygen
Magnesium + water (consider phenolphthalein results)
Mg(s) + 2H2O(l)  Mg(OH)2(aq) + H2(g)
Calcium + water (consider phenolphthalein results)
Magnesium + hydrochloric acid
Mg(s) + 2HCl(aq)  MgCl2(aq) + H2(g)
Calcium + hydrochloric acid
C. Group IIIA Elements: Observations and balanced equations.
Aluminum + oxygen
Aluminum + water
Aluminum + hydrochloric acid
D. Group IVA Elements: Observations and balanced equations.
Carbon + water
Carbon + hydrochloric acid
E. Group B Elements: Observations and balanced equations.
Copper + water
Zinc + water
Copper + hydrochloric acid
Zinc + hydrochloric acid
QUESTIONS
Answer all questions in your laboratory notebook.
1. What trend(s) can you see in your data for the relative reactivities of sodium and potassium and
their respective position on the periodic table?
2. Compare the similarities and differences in the properties of the Group IIA elements with the
Group IA elements you investigated. Use the electron configurations and the position of these
elements on the periodic table to explain your observations.
3. How did the reactivities for the representative elements of Group IIIA and Group IVA compare to
each other and to the reactivities of the elements you investigated in Group IA and IIA? Be
specific and give examples to illustrate your findings.
4. Compare the similarities and differences in the properties of the two transition elements you
investigated. Is this behavior consistent with their relative position in the periodic table and
briefly explain why or why not?