Transcript Atomic Emissions LAB Questions

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