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1 Chemistry Atomic Emissions LAB: A. Briefly describe a way to excite electrons in a sample of a compound from their ground state. HEAT THEM UP WITH GAS.

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Presentation on theme: "1 Chemistry Atomic Emissions LAB: A. Briefly describe a way to excite electrons in a sample of a compound from their ground state. HEAT THEM UP WITH GAS."— Presentation transcript:

1 1 Chemistry Atomic Emissions LAB: A. Briefly describe a way to excite electrons in a sample of a compound from their ground state. HEAT THEM UP WITH GAS IN A BUNSEN BURNER. B. When electrons in a sample of a compound move from their excited states to respective ground states, what form of energy is emitted? ELECTROMAGNETIC RADIATION. Can this energy always be seen by the unaided eyes? Explain. NO, MOST EM RADIATION IS NOT VISIBLE WITHOUT SPECIAL LAB TOOLS.

2 2 Chemistry Atomic Emissions LAB: C. How does the size of an electron cloud change when excited electrons move back to their ground states? AS ELECTRONS DROP DOWN ENERGY LEVELS, THE TOTAL ELECTRON CLOUD SHRINKS (BECOMES SMALLER). D. Compare and contrast the emission spectrum and absorption spectrum for an element. EMISSION SPECTRUM— BLACK BACKGROUND WITH COLORED SPECTRAL LINES; ABSORPTION SPECTRUM—COLORED BACKGROUND WITH BLACK ABSORPTION LINES.

3 3 Chemistry Atomic Emissions LAB: D. Compare and contrast the emission spectrum and absorption spectrum for an element.

4 4 Chemistry Atomic Emissions LAB: E. How do the emission spectra of different elements compare? THEY SHOW SPECTRAL LINES OF COLOR REPRESENTING ELECTRONS MOVING FROM THE EXCITED STATE TO THE GROUND STATE. CONTRAST— EACH ELEMENT HAS A UNIQUE SET OF SPECTAL LINES (IS LIKE A FINGER PRINT). F. Why is it possible for a sample of the element hydrogen, in which each atom only has one electron, to have an emission spectrum with more than one color of light? A SAMPLE HAS MANY ATOMS; EACH ELECTRON IN EACH ATOM WILL MOVE FROM IT’S EXCITED STATE TO GROUND STATE ONE OF FOUR DIFFERENT WAYS.

5 5 Chemistry Atomic Emissions LAB: G. How would the width (spacing) between energy levels in the electron cloud for different elements affect the amount of energy released as electrons move from their excited states to respective ground states? EACH ELEMENT HAS A UNIQUE SPACING OF ENERGY LEVELS IN ITS ELECTRON CLOUD. THE SPECIFIC WIDTH AFFECTS HOW FAR ELECTRONS DROP AS THEY MOVE FROM THEIR EXCITED STATE TO GROUND STATE. THE WIDER (MORE SPACE) FOR AN ENERGY LEVEL, THE FARTHER THE DROP BY AN ELECTRON AND MORE ENERGY IS RELEASED AS RADIATION.

6 6Chemistry Atomic Emissions LAB: Post-lab questions review: Post-lab questions review: 1. They will have the same basic colors but are different for shade or intensity. 2. There are rarely similarities for the secondary components of compounds tested in a flame. 3. The initial component of compounds has the greatest role determining flame color.


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