Electron Configuration and
Energy Levels:
Ground state:
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All the electrons in an atom have the
lowest possible energies
Most stable electron configuration
Example: Sodium (Na)
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Pictures show all the
electrons in a sodium atom
Neutral Sodium has 11
protons (p+) and 11
electrons (e-)
First layer fills up with 2
electrons - 9 left over
Next layer fills up with 8
electrons - 1 left over
Last electron is all alone in
the next layer
All of the Electron Shells
Electron Energy Levels:
Analogy: staircase.
•Can stand on a stair, not between stairs.
•It takes energy to raise from a lower
stair to a higher stair.
•In the same way, electrons can be in
lower or higher energy level but not in
between.
Electron Configuration and
Energy Levels:
Electrons can not exist between energy
levels (shells).
 They must jump from one level to the next.
 Energy must be added to atom for
electron to jump to higher energy level.
 When electron falls back to it’s original
state, energy is released as specific
wavelength of light.
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Electron at
Ground State.
Electrons become
excited, and
move to a higher
energy level.
Add energy in the
form of heat.
Electron
returns
to
Ground
State
Energy
is given
off as
light.
Emission Spectrum
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Each element has different “energy staircase” ,
i.e. unique series of electron energy steps.
To move between steps, electrons absorb or
emit specific amounts of energy,
Amount of energy corresponds to specific
wavelengths (colors) of light.
Emission spectrum: unique series of energy
differences (i.e. colors) between steps allows
identification of elements by light energy they
emit.
Red . Orange . Yellow . Green . Blue . Indigo . Violet
Red
Long wavelength
Orange
Less Energy
Yellow
Green
Blue
Indigo
Violet
Short wavelength
Greater Energy
Flame Test
We will place samples of elements into a
flame.
 This will add energy to the atom in the
form of heat.
 The electrons will them become excited,
and jump to a higher energy level.
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Flame Test
Then the electrons will return to their
original ground state.
 As they return to a lower energy level, the
energy will be given off in the form of light.
 Different elements will have different flame
colors because of their unique electrons.
 This characteristic spectrum can be used
to identify an element.
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