Name: __________________________________ Date: __________________ Period: _______
Light Spectra and Flame Test
Background:
Electrons in an atom can jump up or down from one energy level to
another by absorbing or releasing energy. This energy is often released in
the form of light of a particular color. Most of the time the color that is
observed is actually a blend of several colors. When viewed through a
diffraction grating or a spectroscope, the separate colors can be observed
as lines. These colors correspond to the energy released as electrons jump
down to a lower energy level. Atoms that use more energy levels produce
more lines of color.
The particular pattern of colored lines of light is unique for every
element and is called a spectrum. In this way, elements in stars can be
identified by looking at the lines of color in the star’s light.
Part 1: Line spectra of Some gas elements
The elements we will observe first will be gases. For each gas, use
the spectroscope to observe the spectrum of colored lines. Draw the
pattern of colored lines in the space as accurately as you can.
Element Name: _______________________
Violet
Blue
Green
Yellow
Orange
Red
Orange
Red
Element Name: _______________________
Violet
Blue
Green
Yellow
Name: __________________________________ Date: __________________ Period: _______
Element Name: _______________________
Violet
Blue
Green
Yellow
Orange
Red
Orange
Red
Orange
Red
Orange
Red
Element Name: _______________________
Violet
Blue
Green
Yellow
Element Name: _______________________
Violet
Blue
Green
Yellow
Element Name: _______________________
Violet
Blue
Green
Yellow
Part 2: Flame test of identification of metals
The color of light produced is a characteristic property of the element.
Many metals can produce beautiful colors when energy is added in the
form of heat. This property is useful in the creation of firework displays.
Materials:
Goggles & Apron
Burner
200mL of distilled water
Small Pan
7 Q-Tips
Chemical Sample (Pea size amount)
Name: __________________________________ Date: __________________ Period: _______
Procedure:
***Goggles & apron on and light the burner only when you need it.***
1. Retrieve a pea-size sample of the copper powder.
2. Dip the q-tip in to the water then into the copper sample so that some
of the copper crystals stick to the q-tip.
3. Place the q-tip into the flame so that the crystals are fully in the flame
(do not place to much of the q-tip in the flame or it will melt and ruin
your experiment.)
4. Record the observed color of the flame in the table below.
5. Dispose of the extra chemical and cool q-tip in the trashcan.
6. Clean the pan and repeat the steps for barium, strontium, calcium,
sodium, potassium, and lithium.
Data Table:
Chemical
Copper
Barium
Strontium
Calcium
Sodium
Potassium
Lithium
Color Observed
7. Obtain a sample of an unknown compound. It will contain one of the
metals you observed.
a. Record the number of the compound you chose here: _______
b. Repeat the experiment with your unknown compound.
i. What color did you observe? ______________________
ii. Which chemical is your unknown? __________________