The Shri Ram School, Moulsari Campus
Subject: Chemistry
Topic: Metals – Lab
Class: IG - IX
Name………………………… Sec……… Date………
Criteria
Total
Score
Score
Lab report
1
2
3
4
5
Timeliness
1
2
3
4
5
Lab skills
1
2
3
4
5
Approach towards
task
1
2
3
4
5
Objectives
The objectives of this lab are to:
a. Perform flame tests of metal cations in order to observe their characteristic colors
b. Relate these results to the types of electronic transitions occurring in these elements
c. Practice writing electron configurations for these (and other) elements
LAB REPORT
UNIT : Metals
Chemistry Lab : Flame Tests
Adapted from Essential Lab Manual for Chemistry – Timberlake
Guidelines to Writing a Chemistry Lab Report
1. Statement of the Problem:
 What question(s) are you trying to answer?
2. Hypothesis:
 Write a possible solution for the problem.
 Make sure this possible solution is a complete sentence.
 Make sure the statement is testable; an if-then statement is recommended to illustrate what
criteria will support your hypothesis (and what data would not support the hypothesis).
3. Materials:
 Make a list of ALL items used in the lab.
4. Procedure:
 A procedure should be easy to follow. It should have step-by-step directions for conducting
the experiment. Often it includes a sketch of how to set-up the experiment. The directions
may be numbered to be sure they are done in the correct order.
5. Results (Data):
 This section should include any data tables, observations, or additional notes you make during
the lab.
 All tables, graphs and charts should be labeled appropriately.
6. Discussion:
 This is where you discuss your results.
 It should not include "I", "we", "my", etc.
WRONG
RIGHT
- "I mixed the two solutions
- "The two solutions were mixed and a precipitate
and a precipitate formed".
formed"
- "A precipitate formed upon mixing of the
solutions"
- This should include facts without "feelings”. For e.g. “This was a fun lab and I learned a
lot” or " It was exciting.
7. Conclusion:
 This is a brief summary (1 paragraph, about 5-6 sentences) of the entire experiment.
 Accept or reject your hypothesis.
 EXPLAIN why you accepted or rejected your hypothesis using data from the lab.
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Introduction
The arrangement of electrons in an atom allows us to account for the chemistry and properties of
elements. In this lab, you will use both your knowledge of electron configurations and lab observations to
characterize the properties of known compounds and identify unknown compounds using their
properties.
This lab relies on the use a flame test to identify elements. This test is performed by burning a
known or unknown compound in an open flame. The colors seen while burning a compound can give a
chemist clues to both the identity of the element and its electron configuration.
Background
Electromagnetic Radiation
If you hold your hand a few inches from a brightly glowing light bulb, what do you feel? Your hand
gets warmer. The “light” from the bulb somehow transmits energy to your hand. The same thing
happens if you move close to the glowing embers of wood in a fireplace – you receive energy that makes
you feel warm.
In all of these examples, energy is being transmitted from one place to another by light. The energy
that we call light is also called electromagnetic radiation. Light (or, electromagnetic radiation) travels as
waves, just like the waves you can see in the ocean or a swimming pool. Light waves have three main
properties: wavelength, frequency, and speed. In this lab, we will focus mainly on wavelength.
The wavelength of a wave is the distance between two consecutive wave peaks. This is shown
below:
When light has different wavelengths, it carries different amounts of energy. The varied wavelengths and
amounts of energy in a light wave are what cause the color of a light.
Emission of Energy by Atoms
As we will see in this lab, the colors of the flames created by burning different compounds results
from the atoms in the compound releasing energy in the form of light, or electromagnetic radiation. The
heat from the flame applied to the compound causes the atoms to absorb energy – in chemistry, we say
that this causes atoms to become excited. When an atom is excited, it needs to release this extra energy
and it does so by releasing the energy in the form of light.
The color of the light that is emitted (or released) from an atom corresponds to how much energy a
given atom is releasing. This property can be used to identify elements in a compound because when
burned, elements give off a specific color. For example lithium creates a red color.
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1. Statement
2. Materials:
3. Procedure:
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of the Problem:
4. Results
(Data):
Fill in the following table with the electron configuration of each element and the color which the
element produced in the flame test.
Electron Configuration (For Elements
beyond atomic number 20 write the
valence electron only)
Flame Color
Li
K
Ba
Sr
Cu+2
Na
Unknown
(Write Element Name)
5. Discussion:
Use the following electromagnetic spectrum to answer the question on the next page.
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High-energy light waves have shorter wavelengths. Low-energy light waves have longer wavelengths.
Based on this information and the electromagnetic spectrum on the previous page, place the
following elements of the scale below from lowest energy to highest energy:
Ca, K, Ba, Sr, Cu, Na
Lowest Energy
Highest Energy
a. How can a flame test be used to identify an unknown element?
b. Why did each element in this experiment produce a different color flame?
c. What is the correlation between the color that an element produces and the amount of energy that is
being released?
d. What evidence is there that the colors observed in the flame tests are due to the metals, and not the
nonmetals in the compounds tested?
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6. Conclusion:
a. What was the identity of your unknown compound?
b. How did you come to this conclusion?
7. Precautions:
a. Were there any sources of error in this experiment or results that you could not explain? Give a
description of these and how you could make the experiment better if performed again.
b. List any three precautions observed by you during this lab.
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