Flame Tests

1
Flame Tests

• Lets excite some electrons

2
Theory

• When elements are heated, their electrons may
  move to an excited state. The electrons then
  return to their ground state by releasing EMR.

3
Theory

• Each element will release a specific set of
  wavelengths of EMR (atomic emission spectrum)
  that allow us to identify the element.
• (Think Atomic Finger Print)

4
Theory

• One method of observing these emission spectra
  is by heating a small amount of an element until
  it glows (e- are excited) and observing the color
  of the flameThis is known as a flame test.

5
Objectives

• Develop a reference table that lists the flame
  color of various metal ions.
• Identify seven unknown solutions using your
  reference table.

6
Procedure

• I will show you how to do the test, but your
  group will develop your own process for
  accomplishing the objectives.

7
Helpful Info

• You will be working with
• Sodium
• Strontium
• Copper
• Barium
• Potassium
• Calcium
• Lithium
• Sodium/Potassium Mixture
• Distilled water

8
Helpful Info

• You will have 7 unknowns to identify A, B, C, D,
  E, F, G
• The unknowns must be from the list of metal ions
  previously given to you.
• Record you observations in table format. Do not
  record information in anecdotal form.
• You may work with a partner.

9
Questions to answer

• Give at least two reasons why the flame tests may
  sometimes be invalid.
• What is the purpose of the cobalt glass in this
  experiment?