Bohr’s Shell Model
EXCITED
state
e–’s absorb
(+) energy,
move to
outer
levels
(n=2 to n=5)
5
2
e–’s emit
(–) energy,
move back
to inner
levels
(n=5 to n=2)
GROUND
state
∆E quantum: amount of energy
absorbed or emitted as electrons
transition fixed energy levels.
Electron Energy and Light
The distance between same points on
wavelength () (m)
adjacent waves is the _______________.
The number of waves passing a point per
frequency () (Hz)(s–1)
unit of time is the ______________.
If both waves
move at the
same speed,  and  are inversely proportional
which has
more energy?
R
O
Y
G
B I V
Electromagnetic Spectrum
Lowest Energy
Highest Energy
(higher ) (shorter )
All EM radiation travels at the same speed:
the speed of light (c), 3.00  108 m/s.
joules (J)
c =  (given on test) E = h
(c) speed of light
(h) Planck’s constant
= 3.00 x 108 m/s
= 6.63 x 10–34
shorter 
higher E
higher  , _______
higher  , ______
(inversely)
(directly)
Calculate energy (E) from
frequency () or wavelength ():
↔
↔E
Sample Calculation 1:
c = λ
Calculate the wavelength of the yellow light
emitted by a sodium lamp if frequency of the
radiation is 5.10 x 1014 Hz.
(3.00 x 108) = λ (5.10 x 1014)
(3.00 x 108) = λ
(5.10 x 1014)
λ = 5.88 x 10–7 m
Sample Calculation 2:
c = λ
Calculate the frequency of blue light with a
wavelength of 6.05 x 10–7 m (or 605 nm).
(3.00 x 108) = (6.05 x 10–7) 
(3.00 x 108) = 
(6.05 x 10–7)
 = 4.96 x 1014 s–1
Sample Calculation 3:
E = h
Calculate the energy of the yellow light
emitted by a sodium lamp if frequency of
the radiation is 5.10 x 1014 Hz.
E = (6.63 x 10–34) (5.10 x 1014)
E = 3.38 x 10–19 J
Sample Calculation 4:
c = λ E = h
Calculate the energy of blue light with a
wavelength () of 6.05 x 10–7 m (or 605 nm).
c = λ
(3.00 x 108) = (6.05 x 10–7) 
(3.00 x 108) = 
(6.05 x 10–7)
 = 4.96 x 1014 s–1
E = h
E = (6.63 x 10–34) (4.96 x 1014)
E = 3.29 x 10–19 J
Quick Quiz!
1. Which of the following relationships is true?
A. Higher-energy light has a higher frequency
than lower-energy light.
B. Higher-energy light has a longer
wavelength than lower-energy light.
C. Higher-energy light travels at a faster
speed than lower-energy light.
D. Higher-frequency light travels at a slower
speed than lower-energy light does.
Quick Quiz.
2. The energy of EM radiation is greatest for…
A. visible light.
B. ultraviolet light.
C. infrared light.
D. X-ray radiation.
Quick Quiz.
3. The longer the wavelength of light, the…
A. higher the frequency.
B. higher the energy.
C. lower the frequency.
D. lower the energy.