**Unformatted text preview: **e orbit to another by either emitting or
absorbing photons with specific frequencies. Thus:
• To move to a higher energy orbit (a greater value of n) an
electron must _absorb
_____________________energy.
• To move to a lower energy orbit (a lower value of n) an
electron must emit energy.
• The frequency of the absorbed
or emitted energy corresponds
exactly to the energy difference
between the orbits.
those two 20 10 05-Sep-13 Ground state Excited states Absorption and emission energy (cont) Clip
21 Absorption and emission energy (cont)
1 λ =R 1
m2 - 1
n2 m: shell the transition
is to (inner-shell)
higher We use the Rydberg
equation to identify
spectral lines n: shell the transition
is from (outer-shell) higher where n > m
R: Rydberg constant
1.097x10-2 nm-1
or
3.29x1015 Hz Aside: c = λ · v 1
1
= R 2 − 2 λ
n
m
1 1 1 ν = Rc 2 − 2 n
m
22 11 05-Sep-13 n=1 to n=2-->more
distance and need
more energy. as it
is close to the
nucleus,it requires
more force bcoz of
the attraction. Which requires greater energy, an
electron promoted from n=1 to n=2, or
an electron promoted from n=3 to n = 4?
n=1 to n=2
Which releases a photon with greater
frequency, an n = 5 to n = 4 transition or
an n = 3 to n = 2 transition? Α)
Α) ν=R(1/42 – 1/52)= 7.4x1013 Hz
vs Β)
Β) ν=R(1/22 – 1/32)= 4.6x1014 Hz Which releases a photon with greater
wavelength, an n = 5 to n = 4 transition
or an n = 3 to n = 2 transition?
Α)
Α) λ=c/ν= (3 x 108 m/s)/(7.4 x 1013 Hz)
•λ= 4.05x10-6 m or 4052 nm near infrared
Β)
Β) λ=c/ν= (3 x 108 m/s)/(4.6 x1014 Hz)
•λ= 6.56x10-7 m or 656 nm red light
23 12...

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