unresolved: the collapsing atom paradox unresolved: chemical periodicity
TRANSCRIPT
Unresolved:The Collapsing Atom Paradox
Unresolved: Chemical Periodicity
Unresolved: Heated metal atoms emit colored light
Unresolved: Electrified gases emit Line Spectra
Unresolved: Rydberg Equation
22
21
111
nnRH
n2 > n1… whole numbers
RH = 1.097 x 107 m-1
New model…..
Electrons as particles in Orbit (Bohr)
Now we have angular momentum, L, whichBohr hypothesizes
Is QUANTIZED
And we need to equate the centripetal (accelerating and electrostatic) forces
…the energy of an electron in
orbit:2
-18 J 102.18
n
• The lowest energy state of an atom is called the ground state (an electron with n = 1 for a hydrogen atom)
Absorption and emission of energy by the hydrogen atom. An electron that absorbs energy is raised to a higher energy level. A particular frequency of light is emitted when an electron falls to a lower energy level.
Bohr’s Model
• The lowest energy state of an atom is called the ground state (an electron with n = 1 for a hydrogen atom)
Absorption and emission of energy by the hydrogen atom. An electron that absorbs energy is raised to a higher energy level. A particular frequency of light is emitted when an electron falls to a lower energy level.
Bohr’s Model
…the energy of an electron in orbit: 2
-18 J 102.18
n
• The lowest energy state of an atom is called the ground state (an electron with n = 1 for a hydrogen atom)
Absorption and emission of energy by the hydrogen atom. An electron that absorbs energy is raised to a higher energy level. A particular frequency of light is emitted when an electron falls to a lower energy level.
Bohr’s Model
…the energy of an electron in orbit: 2
-18 J 102.18
n
Ephoton = hν = hc/λh = 6.63 x 10-34 J·sc = 3.00 x 108 m/s
• The lowest energy state of an atom is called the ground state (an electron with n = 1 for a hydrogen atom)
Absorption and emission of energy by the hydrogen atom. An electron that absorbs energy is raised to a higher energy level. A particular frequency of light is emitted when an electron falls to a lower energy level.
Bohr’s Model
…the energy of an electron in orbit: 2
-18 J 102.18
n
Ephoton = hν = hc/λh = 6.63 x 10-34 J·sc = 3.00 x 108 m/s
2218 11
1018.2hl
electron nnJxE
Unresolved:Multi-electron atomic spectra
New model…..
Einstein saysE = mc2
Einstein & Planck sayEphoton = hn
mv
hmc
h
mchc
hE
2
for a photon
for any object
Electrons as Orbital Standing Waves
If this were a standing sound wave what would you hear
at the nodes?
If this were a standing electron wave what would you detect at the nodes?
0 5 10 15 20 250
0.5
1
1.5
2
2.5
3
First Ionization Energy vs Atomic Number
1st...
IE (
kJ/m
ol
x 10
-3)
0 5 10 15 20 250
2
4
6
8
10
12
14
16
Ionization Energy vs. Atomc Number
1st IE2nd IE3rd IE
IE (
kJ/m
ol
x 10
-3)
electron waves of an electron trapped in a corral of iron atoms
Electrons as Orbital Standing Waves
If this were a standing sound wave what would you hear
at the nodes?
0 5 10 15 20 250
0.5
1
1.5
2
2.5
3
First Ionization Energy vs Atomic Number
1st...
IE (
kJ/m
ol
x 10
-3)
0 5 10 15 20 250
2
4
6
8
10
12
14
16
Ionization Energy vs. Atomc Number
1st IE2nd IE3rd IE
IE (
kJ/m
ol
x 10
-3)
Electrons as a linear standing wave
Where L is the total length, λ is the wavelength, and n is an integer.
n
L2
The only waves that can occur are those for which a half-wavelength is repeated exactly a whole number of times (n times).
n
L2
(n = 3 in this case)
Electrons as a linear standing wave