do now… draw the diagram that reminds you of the correct order of electron orbitals. write out the...
TRANSCRIPT
DO NOW…
Draw the diagram that reminds you of the correct order of electron orbitals.
Write out the electron configuration for Pd in full form and in noble gas notation
Homework = Read 5.3 AGAIN & #’s 16-18,21,42,44-47
So how am I supposed to remember the order of the rooms?
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2
4d8
46 total e-
Pd
orbitals?
Noble Gas Notation = [Ar] 5s24d8
If e- don’t really stay in hotel rooms…
CORRECT VOCABULARY
Floor = Principal Energy Level
Suite = Sublevel
Room = Orbital
3s
2p
2s
1s1s22s1Li
Review....Orbital ShapesReview....Orbital Shapes
Maximum Number of Electrons In Each SublevelMaximum Number of Electrons In Each Suite Type
Suite # of Maximum # Type rooms of electrons
s 1 2
p 3 6
d 5 10
f 7 14
Sublevel
Sublevel orbital
s
Excitation of Hydrogen Atoms
Return to Ground State
An Excited Lithium Atom
Photon ofred lightemitted
Li atom inlower energy state
Excited Li atom
Ene
rgy
Chemist Humor
Question:Question: Why does hamburger have lower energy than steak?
Answer:Answer: Because it’s in the ground state.
The Electromagnetic Spectrum(BIG FANCY WORDS FOR.... LIGHT)
Visible part of EM Visible part of EM SPectrumSPectrum
PRISM
Slit
Ray of
White Light
Waves 1/33,000” long
Waves 1/70,000” long
RedOrangeYellowGreenBlueIndigoViolet
400 nm – 700 nm
BIG topics...copy these down Light (electromagnetic radiation) particle/wave dual nature of light c, λ, ט , E & hQuantum vs. Photon (p. 128, p.144)
Quantum theory (wave mechanical model)Bohr model of atom (ENERGY LEVELS)Atomic absorption/emission & spectraOrbital shapes & Heisenberg uncertainty
Electron configurationsorbital, e- configuration noble gas notationAufbau, Pauli, & Hund
Waves
Wavelength () - length of one complete wave. Common units: m or nm
Frequency () - # of waves that pass a point during a certain time period (usually per second)Common Units: hertz (Hz) = 1/s = s-1
Amplitude (A) - distance from the origin to the trough or crest (height of one wave)
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Frequency
O’Connor, Davis, MacNab, McClellan, CHEMISTRY Experiments and Principles 1982, page 166
1 second
Frequency
4 cycles/second = 4 hertz
12 cycles/second = 12 hertz
36 cycles/second = 36 hertz
Vocabulary of a Wave
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 324
A
c = speed of light = 2.998 x 10 8 m/s
(really fast, true for every kind of light!)
Quantum TheoryQuantum Theory
Max Planck (1900)
Observed - emission of light from hot objects
Concluded - energy is emitted in small, specific amounts (quanta)
Quantum - minimum amount of energy gained or lost by an atom
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Electromagnetic Radiation = PHOTONS
Light as a wave
Light as a stream of energy
(packets of photons)Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 325
IMPORTANT LIGHT EQUATION #1 Frequency & wavelength are inversely
proportional
c = c: speed of light (2.998 108 m/s): wavelength (m, nm, etc.): frequency (Hz or s-1)
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Example Problem for Equation #1
Find the frequency in Hertz of microwave radiation with a wavelength of 7.5 10-3 m.
GIVEN:
= ? = 7.5 10-3 mc = 2.998 108 m/s
WORK: = c
= 2.998 108 m/s
7.5 10-3 m
= 4.0 x 1010 s-1
= 4.0 x 1010 HzCourtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
IMPORTANT LIGHT EQUATION #2
E: energy (J, joules)h: Planck’s constant (6.6262 10-34 J·s): frequency (Hz)
E = h
• The energy of a photon is proportional to its frequency.
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Energy of Waves – It takes more energy to travel at a higher frequency…
Low frequency
High frequency, short wavelength
Amplitude
Amplitude
Low frequency,long wavelength
short wavelength
Red and Blue Light
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 325
Photons - particle of light that carries a quantum of energy
Example problem for Equation #2
Find the energy of a red photon with a frequency of 4.57 1014 Hz.
GIVEN:
E = ? = 4.57 1014 Hzh = 6.6262 10-34 J· s
WORK:
E = h
E = (6.6262 10-34 J· s) (4.57 1014 Hz)
E = 3.03 10-19 J
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Example problem using BOTH Example problem using BOTH Equations…Equations… Find the energy of a photon with a
wavelength of 1.0 x 10-3 nm.
GIVEN:
h x 10-34 J s
c = 3.00 x 108 m/s
= ?
= 1.0 x 10-3 nm = ???? m
WORK: = c = 3.00 108 m/s 1.0 x 10-12 m = 3.0 x 1020 s-1
E = hv c = λv
= (6.626 x 10-34 J s)(3.0 x 1020s-1)
E = 1.99 x 10-13 J
Equations with Wavelength and Equations with Wavelength and FrequencyFrequency
E = h
c = c = speed of light (2.998 x 108 m/s) = frequency (s-1)= wavelength (m)
E = energy (Joules or J)h= Planck’s constant (6.626 x10-34 J s) = frequency (s-1)
“nu” “lamda”
Highest energy
Moderate energy
Lowest energy
Common wavelength units for electromagnetic radiation
Picometer pm 10-12 Gamma ray
Ångstrom Å 10-10 X-ray
Nanometer nm 10-9 X-ray
Micrometer m 10-6 Infrared
Millimeter mm 10-3 Infrared
Centimeter cm 10-2 Microwave
Meter m 100 Radio
Unit Symbol Wavelength, (m) Type of Radiation
Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.
Bohr Model of Bohr Model of HydrogenHydrogen
Nucleus
Possible electron orbits
eGreat theory, BUT it turned out to be totally wrong!! Next week we’ll see a better theory
Further away from nucleus means higher energy level…
Bohr Model• electrons exist only in orbits with
specific amounts of energy called energy levels
• Therefore…• electrons can only gain or lose certain
amounts of energy• only certain photons are produced
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Continuous and Line Spectra
light
Na
H
Ca
Hg
400 450 500 550 600 650 700 750 nm
Visiblespectrum
(nm)
Flame Test Emission Spectra
Photographs of flame tests of burning wooden splints soaked in different salts.Photographs of flame tests of burning wooden splints soaked in different salts.
methane gas wooden splint strontium ioncopper ionsodium ion calcium ion
Copyright © 2006 Pearson Benjamin Cummings. All rights reserved.
Example: Emission Spectrum of Hydrogen
410 nm 434 nm 486 nm 656 nm
ATOMIC SPECTRA: See p. 141 before Friday!
Other Elements Each element has a unique bright-line
emission spectrum.
i.e. “Atomic Fingerprint”
Helium
Bohr’s calculations only worked for hydrogen!
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e-e- Ground state
Excited state
Electrons can only be atspecific energy levels,NOT between levels.
Continuous vs. Quantized Continuous vs. Quantized EnergyEnergy
Ene
rgy
A Bcontinuous quantized
Acontinuous
Bquantized
Bohr Model
Energy of photon depends on the difference in energy levels
Bohr’s calculated energies matched the IR, visible, and UV lines for the H atom
1
23
456
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nucleus
Frequency A
Frequency B
Frequency C
n = 2
n = 1
n = 3
A
B
C
A + B = C
DO NOW: Draw this diagram in your notes and take out your HW from Mon & Tues.
DO NOW: Draw this diagram in your notes& take out HW
Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.