The electron configuration of an atom is the spatial and energetic arrangement of electrons in orbitals around an atom. Each orbital defines a region of space around the nucleus that has a specific energy. Electrons can change energy by changing orbitals. Electrons are "excited" to higher orbitals when an atom absorbs energy, such as in a collision with another atom. Atoms give off photons when their electrons return to lower energy levels. An atomic emission spectrum is a series of discrete colored lines, each of which represents the energy transition of an electron from a higher energy excited state to a lower energy state. Because each element has a unique electron configuration, it has a unique atomic emission spectrum. The atomic emission spectrum is the "fingerprint" of the atom and is often used to identify the element. How can atoms have fingerprints when they don't even have fingers? Let's find out!

In this Internet activity, you will discover which elements produce the colors you see in fireworks. You will observe some atomic emission spectra and understand why elements can be identified by their atomic emission fingerprints.

1. Go to Kaboom, and click on the following elements. You'll find the color each element produces in typical fireworks.
   Na     Li     Ba     Sr     Al     Mg     Ca     Cu
   
   
2. An atomic emission spectrum is a series of colored lines that are caused by electrons within atoms returning to lower energy states after being excited by absorbing energy. Go to Spectra of Some Elements, and observe the spectra of the elements shown. Are any two exactly the same? Explain why an atomic emission spectrum is sometimes called the fingerprint of an element.
   
   

Additional Activities

1. The heat from a flame causes many chemicals to produce colored light just as they do in fireworks. Go to How Things Work: Fluorescent Lamps. Read the answer to the first question on this site and explain how metal salts in flames and fireworks produce colored light.
   
   
2. Compare the light emitted by incandescent bulbs to that emitted by halogen bulbs and fluorescent bulbs. Begin by going to How Things Work and choose the topic Incandescent Light Bulbs.